View Full Version : Revox B 795


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bikezappa
01-21-2011, 07:12 AM
There is however one single important difference...

the B291 and H9 have IR remote control built in.

So my B208 Revox remote will operate the B291. I don't need the extra IR reciever that plugs into the table?

dlaloum
01-22-2011, 12:51 AM
I believe so.... can't remember which remote had which functions...

But I believe that the table is considered one of the "tape machines" (ie play forward and back work...)

I have been wanting this feature for my B795 for years.... there's a guy in Germany making an aftermarket plugin to do this for B795 (which had it as an external option) - and you can fit it internally!

But he charges 200euro for the circuit board - and then it needs to be fitted, and a hole drilled in the case for the IR receiver etc....

In any case I can't tell you the details as I have never had the opportunity to try it!

But if you want to swap your B291 for my B795......

steerpike2
01-22-2011, 07:20 AM
On the B208, B201 and B205 handsets, the three buttons <, > and V^ operate the turntable. With the '*' button, these same buttons do cue/review and pause for the CD player.
If you had two turntables and no CD, one TT could be set to 'address 2', in which case it will respond to the CD player instructions instead.

The instructions aren't shared with any of the tape decks, BUT the B202 receiver was universal in that it could be used with tape decks or turntables - it would respond to different commands depending on which it was connected to and configured for.

The B291 also responds to speed change, pitch adjust, and disc size select by IR remote, but only the B210 learning remote could send out the commands to do that.

The B291 also sends out - via its serial port - all its status data. If you have a B203 or B200 these two controllers can use that data and relay it on to other remote devices that have displays (B210, B250, personal computer)

bikezappa
01-23-2011, 08:58 AM
I never knew Revox made a B 210 learning remote!
I have a few B 208 remotes and they have buttons for CD and Phone as you stated.

steerpike2
01-23-2011, 05:16 PM
In that it is wireless and runs on batteries, I suppose you'd call it a remote control - but it's bigger than some peoples whole audio system!

As I mentioned above, it displays the status of all the B200-series components too, since it has bi-directional IR capabilities.

B208 on the left, B210 on the right.
It's functionality is disguised by the relatively few buttons, but it had a whole sequence of menus to access the less commonly used functions.
It also controlled the Lowe-made "ReVox" TV sets and sVHS machine, which used a different IR protocol to the other ReVox handsets.
And it has a com port on it so you can plug it into your laptop and do even more bizarre things. But I'm not aware ReVox released any PC software to take advantage of that.

http://www.studerundrevox.de/images/content/revox_serien/ReVox-B210-und-B20801.jpg

bikezappa
01-24-2011, 08:19 AM
I have one of those Large remotes but it is for the H series. I was so hoping the H series remote would work on the B series.

I plan on selling my complete H series, amp, tuner, cassett and CD with 2 remotes and IR reciever with original boxes and manuals in the future as a set.

steerpike2
01-24-2011, 01:39 PM
I have one of those Large remotes but it is for the H series. I was so hoping the H series remote would work on the B series.

I assume from the wording of your post that it does not?

I have technical documentation for the B2xx IR stuff, but not a thing on the H series - so I have no knowledge on the protocols.
(For the B210, it uses the Nokia/ITT FM protocol to sent out data, but the Philips RC5 at a unique carrier frequency of around 300kHz to receive data back.)

I'd love to get hold of either of a B210 or an H210 to play with.

bikezappa
01-25-2011, 08:15 AM
I also would like to get a B210 to play with. The first thing I did after purchase was to try to see if either of the two H series remotes would work on the B series. Nope. They look the same. I don't see any method of programing the H 210 however. You say the B 210 can be programed. Any more information about how to do that.

steerpike2
01-25-2011, 02:12 PM
The whole "H" series was supposed to be simplified, easier to use, without the really exotic and probaly never used features of the B200 line up; so the programability may have been taken out of the H210.

If they were electrically the same - you could possibly re-programme the EEPROM in the H210 to make in a B210!?
<UPDATE> the H210 seems to have fewer buttons than the B210; the H208 definately has fewer buttons than the B208.

The B210 German flyer roughly translated says:
"
Universal table-top remote control for all Revox audio & video devices of the series 100, 200, 200S; more than a substitute for the B208.
B210 Transmission: IR signal from & to B200 with B207 tranceiver. Format compatible with B208 and previous remote controls.
8bit CPU, 8MHz, 34kB RAM, 64kB ROM
Learnable for unfamiliar IR codes, carrier modulated or unmodulated.
B207 Transmission: carrier-modulated RS232
Programming: via special menu with keyboard, or via copy cable (data transfer from second B210)
"

The circuit forthe B210 also shows two IR receiver diodes, One labelled "IN IR RS232", the other "Learn IR".
I have no literatue at all on the H210.

(We were discussing a bit on the remotes here more in relation to the B710:
http://www.audiokarma.org/forums/showthread.php?t=342353
I made mention of a project i'm on/off working on to decode the entire Revox IR command set with a PIC. So when it gets done I'll publish the info and source code.)

c_dk
01-25-2011, 04:20 PM
I worked for and was a Revox dealer from 80 til 94. Without reading all 18 pages of posts what IR parts and documentation are you all looking for?

steerpike2
01-25-2011, 04:56 PM
I worked for and was a Revox dealer from 80 til 94. Without reading all 18 pages of posts what IR parts and documentation are you all looking for?

Hi C-DK

Technical details of the IR protocols used by the H210, and the handset's capabilities (processor / RAM / ROM).

The www shows zero on that remotes abilities, so if you know it or have the documentation, it would be very interesting & enlightening.

Actually, very little H-series technical info is out there, and the H-series sales brochures were really crappy - trying to be all arty and aloof - neither saying nor showing anything useful about the products.

The B203 (controller/timer) has PC board locations for IR transmitting components, but nothing installed. So it looks like they thought about making it natively bidirectional, but then decided to pack the IR transmitting parts into the B207 instead.

c_dk
01-25-2011, 10:53 PM
I will dig around in my NOS and see whats there. Now I am going way back but I seen to remember a Pioneer TV remote that could accept and learn B&O, Revox,and Tanberg remote codes. It was one of the few, maybe the only learning remote, here in the States that would control European equipment reliably.

dlaloum
01-25-2011, 11:21 PM
I still have an asian learning remote that I purchased specifically for its Revox Learning capability... SDS-2000

I ended up pretty much getting rid of most of my Revox gear since - so it is now an orphan...

I originally selected it after working out that there was a high likelihood that this was the same remote used by Revox for its later (post H) series...
Obviously made in China for Revox, and then sold under both the asian brand and the Revox Brand.

I even have the programming software (PC, RS232 interface..) and the charging / docking stand etc....

Anyone interested? (I really should move it on, as it has been doing nothing but gathering dust!)

guiller
02-02-2011, 07:53 AM
This is an update on my B795. It works well mechanically and it's fitted with a Ortofon M20 E MM cart. It plays with great sound, except that all records sound noisy, more that in my other TTs. I've checked the tracking force with a digital scale and adjusted it to 1 gram, as recommended. The only other screw to play a bit is the one that controls the maximum depth that the cart can attain without being constrained by the record on the TT's plate. I was thinking about playing a bit with it, although the cart seems to be in the correct position for the VTA, i.e., the lower portion of the stylus case is parallel to the record. Any hints on this?

boyerd001
02-02-2011, 09:27 PM
I've got 3 ReVox TTs (2-B791s and 1-B790) and they are all DEAD QUITE with properly clean records.

Unfortunately, to hear vinyl at its best you need a Vacuum Record Cleaning Machine. I use a Nitty Gritty 1.5FI, but there are other good machines. Research your cleaning solutions or formulate your own, the important thing is to liberally soak the record AND THEN VACUUM THE SOLUTION OFF until the record is dry!

Sorry, there are no other effective ways to a clean vinyl record. Adjusting the ReVox TT is not the final solution.

Dale


This is an update on my B795. It works well mechanically and it's fitted with a Ortofon M20 E MM cart. It plays with great sound, except that all records sound noisy, more that in my other TTs. I've checked the tracking force with a digital scale and adjusted it to 1 gram, as recommended. The only other screw to play a bit is the one that controls the maximum depth that the cart can attain without being constrained by the record on the TT's plate. I was thinking about playing a bit with it, although the cart seems to be in the correct position for the VTA, i.e., the lower portion of the stylus case is parallel to the record. Any hints on this?

dlaloum
02-03-2011, 03:03 AM
What are your other TT's? (Arms? Cartridges? Styli?)
What is your cleaning routine?

guiller
02-03-2011, 06:32 AM
I've got 3 ReVox TTs (2-B791s and 1-B790) and they are all DEAD QUITE with properly clean records.

Unfortunately, to hear vinyl at its best you need a Vacuum Record Cleaning Machine. I use a Nitty Gritty 1.5FI, but there are other good machines. Research your cleaning solutions or formulate your own, the important thing is to liberally soak the record AND THEN VACUUM THE SOLUTION OFF until the record is dry!

Sorry, there are no other effective ways to a clean vinyl record. Adjusting the ReVox TT is not the final solution.

Dale

Thanks to all who provided feedback.

As I said, the records sound noisier on this TT than on others (Clearadio Emotion, Thorens TD 126 Mk 2). I've got a Clearaudio Smartmatrix RCM (one of the best out there, IMHO) and clean all my records. I occasionally use the wood glue or steam methods for hardcore cases. Cleaning records is not the issue. There is some point here, perhaps the stylus should be replaced (although it looks good visually). I realize that the height does not change anything, but cleaning the records is something I do on a regular basis and cannot be blamed for the extra amount of noise level on this TT. I will recheck the manual again to verify all the settings regarding the positioning of the cart, but when I mounted it a few months ago everything was done according the manual in all detail. Visually it looks good when playing a record. I will take a picture and upload it tonight, if possible. Nothing seems to be wrong in either the cart tracking ability or in the movements of the tonearm. Everything looks good, but there is this annoying amount of extra surface noise. As a last resource, I will replace the cart for a new one (I was thinking about a AT high compliance cart like AT440mla). But this is a painful road that I would not like to traverse unless all other options are discarded. Perhaps buying a new stylus for the Ortofon would be the easiest way, although it costs about the same as a new AT cart!

dlaloum
02-03-2011, 07:16 AM
Couple of things...

1) I assume you have used Dales method of checking the ride height (50% of arm visible down past the sensor circuit board when playing)
2) I have an Ortofon VMS30mkII which I believe has the same proportions (size, height etc...) as the M series cartridge you have.... My measurements are as follows:

Cart height to stylus = 15mm
Shim required for correct mounting = 6mm

This beastie requires a HUGE Shim... (6mm is pretty chunky!)

if the shim isn't right, then you probably have a VTA problem (which would possibly explain the noise)

If you don't have shimms - try this:
http://shop.ebay.com.au/asantewood/m.html

Talk to him and ask him for whatever size you want. I had him make me a kit so I have various thicknesses for flexibility - but he is quite happy to make a single at your required thickness.

It is lovely workmanship by the way... and has been working well for me.

bye for now

David

guiller
02-03-2011, 07:24 AM
Couple of things...

1) I assume you have used Dales method of checking the ride height (50% of arm visible down past the sensor circuit board when playing)
2) I have an Ortofon VMS30mkII which I believe has the same proportions (size, height etc...) as the M series cartridge you have.... My measurements are as follows:

Cart height to stylus = 15mm
Shim required for correct mounting = 6mm

This beastie requires a HUGE Shim... (6mm is pretty chunky!)

if the shim isn't right, then you probably have a VTA problem (which would possibly explain the noise)

If you don't have shimms - try this:
http://shop.ebay.com.au/asantewood/m.html

Talk to him and ask him for whatever size you want. I had him make me a kit so I have various thicknesses for flexibility - but he is quite happy to make a single at your required thickness.

It is lovely workmanship by the way... and has been working well for me.

bye for now

David

Hi Davis,

Yes, I have to recheck everything, but as I said, I did a carefully detailed job at the time and certainly remember having paid attention to 1). My first suspect was VTA, but the cart seems to be perfectly parallel to the record. Perhaps I will post a picture. Regarding the shims, I remember that I use all the ones that came with the cart, as none was left. Checking everything again is painful, but perhaps is the only way possible to solve this problem. As I said, it took me about two months to carefully set up the cart following all the literature in detail. One thing is for sure: most TTs are much easier to set up than the Revox, given the way the tonearm is designed.

dlaloum
02-03-2011, 07:35 AM
No Kidding! - and doubly so without the original kit!

I have no way of knowing how many shimms you had and what size they were.... but I will stress (In case we haven't done so often enough) getting the shimming right is critical.

I have now resolved this issue by switching to P-Mount - so I can swap in several different cartridges with very little pain.

Getting there took a while though, and I ended up buying a vernier scale so I could measure things properly.

I also double checked and triple checked things using both Dale's method (thanks for the docs Dale) and the original Kit gauge. My Kit is not complete and was missing some shimms, which led me to a search for shimms, and finally to ordering a set of shimms made up by this guy in Korea.

The combo of the Vernier and the shimms got things up and running quick smart.. (well actually an evenings work... several hours)

Good luck

David

steerpike2
02-03-2011, 07:36 AM
An easy way to play with the VTA without removing the cartridge is to take off the platter mat, or add cardboard spacers under it.
You do have to change the 'bottoming limiter' on the arm to play a disc with a thinner mat.

For shims, I just used some bits cut off the corners of old printed circuid boards, filed to size & drilled.

guiller
02-03-2011, 07:38 AM
An easy way to play with the VTA without removing the cartridge is to take off the platter mat, or add cardboard spacers under it.
You do have to change the 'bottoming limiter' on the arm to play a disc with a thinner mat.

:thmbsp: Many thanks! This is an excellent idea. I will play a bit with this, at least trying to arrive to a diagnosis. If I can conclude that the VTA is wrong, then setting up the cart again won't be as painful as before.

boyerd001
02-04-2011, 08:17 PM
Just one last thought on why the ReVox might have higher LP background noise. The Ortofon M20 E MM mounted on the ReVox has an elliptical stylus I believe, and that may be riding higher in the groove than the other cartridge's stylus that's on the other table. I don't remember you saying what make/stylus that cartridge was, but "fine-line" tips like the AT440MLa ride in the groove lower than ellipticals and can provide a quieter sound since they may be tracking on less damaged groove areas (especially with used LPs). You really need EXACTLY the same cartridge/stylus in both tables before you can say that one table is inherently "noisier" than another.

This awareness of stylus shapes may have been discussed earlier in the thread, forgive the re-posting if it has (thread is starting to get a "wee bit" long!).

Dale

dlaloum
02-04-2011, 09:26 PM
Good point (!) -

Even within the AT family there are the "standard" Line Contact styli, and the exotic Micro Line styli....

The standard LC's tend to be around 40um major radius (width) - examples are Hyperelipticals (V15V), the "small" Shibata, Fineline...

The exotics are mostly around 70um width - large shibata, SAS, MicroRidge, VdH, FritzGeiger, etc...

Elipticals are mostly around 18 to 20 um.

People trying to archive old (worn) recordings often "play
with a range of styli to find the one that best avoids the wear pattern on the disc and reads the unworn vinyl - the wear pattern will of course depend on what it was played with - in addition to how it was recorded etc....

Unfortunately one size does not fit all....

bye for now

David

guiller
02-05-2011, 08:20 AM
In my specific case, I´m pretty much sure the trouble is a wrong VTA value. I performed a few test as Steerpike2 suggested and the level of noise changed, although I was not able to find a point in which it would be gone.

The cart was taken from a Thorens TD 126 Mk where it performed silently, and the same cart with the same records produces a noticiable level of background noise in the Revox. Therefore, I would discard any diagnosis based on the shape of the stylus, in my case.

My plan is to unmount the cart, recheck everything again, and mount it back. If the noise is still there I will order a new cart, perhaps a AT440MLa

dlaloum
02-05-2011, 09:06 AM
The other thing to keep in mind is that the Revox is an "engineers" table...

It is designed to set the cartridge level - and assumes that VTA will be perfectly adjusted at that point. And it is definitely NOT designed for tweaking VTA.

Unfortunately not all stylus/cartridge designers come from the same school... and some designs appear to prefer "non standard" (ie cartridge is not prefectly horizontal) setups..... when that is the case I think the Revox is perhaps not the ideal table for that cartridge and vice versa.

Due to the very short arm, a tiny change in shimming can result in a larger variation in VTA than it would in a standard arm - so extreme caution is advised.
This corollary of the short arm is perhaps another reason why the Revox designers made VTA variation a non option (or at least a very painful & difficult option!)

You gains some and you lose some... swings and roundabouts.... the short arm has advantages and disadvantages - and which you value the most depends on your perspective.

Pio1980
02-05-2011, 10:08 AM
I was never convinced that these TT's designer(s) fully understood vinyl playback requirements re the arm vs record variability and VTA/VRA, pivot-to-tip distance/angle, ect ect. It just comes across as a TT designed by tape transport specialists who examined some competitors turntables and decided to go their own way.
That may sound arrogant but I never liked or was comfortable with what I've seen with the concept and execution of the cart carrier on the Linatrack. That it works at all, more that it usually works well enuff is something else. I don't think line contact stylii are a good option given the VTA/VRA tuning difficulties in any case tho' synergy may be found with almost any fortunate combination.

steerpike2
02-05-2011, 02:10 PM
It just comes across as a TT designed by tape transport specialists who....

I'm rather inclined to agree with this in principle.
ReVox is my all time favourite audio company (maybe because of the following reasons), but I feel they sometimes designed equipment as an excercise in extreme engineering, to show what could be done if you had unlimited access to the technical resources of the parent company and no worries about cost. Their A720 synthesizer tuner is an example - cutting edge technology, but the audio op-amps they used - although extremely costly at the time - spoil its performance.
It's interesting that Studer never tried to make a broadcast turntable.

Conversely, the ReVox turntable was not really built for audio fanatics to tweak or experiment with. All that was supposed to have been taken care of at the factory, so the end user had only to press a single button for playback. A bit like CD was designed for: very good, though not exceptional performance, but ultimate convenience.

As an aside, notice that the B791,795 platters have holes cast into them just at the positions where the 7" and 10" disc peripheries lie. I wonder if they intended at one time to include optical size detection, and then abandoned it (like the Technics SL7, SL10 etc). Might be a fun add-on project for the future!

guiller
02-05-2011, 02:28 PM
I would like to ask people who use the B795 (or similar models) to list the carts they are using, and to give an opinion on their performance (i.e., the level of satisfaction). I am thinking about replacing my Ortofon M 20 E by another cart and thought about the AT440MLa , but perhaps it would be wiser to consider instead those models that have been succesfully tested.

guiller
02-05-2011, 02:48 PM
Wrong post, please excuse me.

dlaloum
02-05-2011, 08:15 PM
As another aside on the design of the Revox TT's....

There is a Revox patent out there for a version of the Linatrack arm with magnetic damping.

So from the sound of it, there were in house plans that had progressed quite a way along the path to a version of the family that would have had:

1) Automatic record size sensor
2) Electro Magnetic Servo arm (servo damping as well?)

Who knows what else?

here is the section from the tonearm patent (US Patent 4170362):

"The disclosed arrangement is of the type for a short tonearm which is guided over the record so that the tonearm remains tangential to the grooves of the record. The tonearm is balanced mechanically on a single point bearing, with the phono cartridge to one side and a counterweight to the other side of the bearing. A permanent magnet fixed to the top of the tonearm interacts with a stationary magnet closely spaced from it to hold the tonearm vertically. The tonearm magnet is a vertical, round, solid cylinder section, while the stationary magnet is a parallelepiped with facing width equal to the diameter of the facing tonearm magnet. This constrains the tonearm to prevent it from tipping to the side, while permitting rotation about the vertical axis and about a horizontal axis through the point bearing and perpendicular to the tangent to the record groove.The improvement comprises that the stationary magnet is provided with a winding. By control of a direct current in the winding, the tonearm can be raised and lowered and the stylus pressure controlled, even while the stylus is tracking in a groove. Futhermore, the tonearm can be magnetically preloaded, so that in the absence of current in the control winding, the tonearm raises to its rest position, thus preventing damage to the record. Various designs are described for determining the interaction of the movable and stationary magnets and the superimposed magnetic field of the control winding."

there are diagrams there as well...

And this is talking about pure Revox/Studer engineering.

For the fidly audiophile stuff you would need to look at what Benz Micro did, under the Empire brand name (while it was owned by Benz) - they purchased whole B291's (I think it was the B291 rather than the B79x series) and heavily modded the arm.

I am still waiting and hoping to see photos of the result - apparently the new arm was made of metail - and went from being low mas to being medium mass, and the Linatrack mechanism was modified to reduce vibration....

I don't think Revox was ever an audiophile company, what they made were consumer versions of studio & broadcast grade equipment.

I have also heard that keen audiophiles (and recording engineers) would upgrade the analogue outputs on Revox Tape machines....

But the other side of that coin, is that the analogue circuits on the B2xx systems (CD, Amps, Tape) were top class - so Revox pulled its analogue socks up as time went on...

And there are Reviews from when the TT was new, none of which are negative, and generally it was up with or beating all competitors at its (expensive!) price point.

It is DIFFERENT.... certainly not worse, and in most ways better than standard pivot arm. There are better Turntables and arms, but to get something that is clearly a step up from a Revox TT requires a step into the stratosphere, and the spending of $10k++ anything below that and you are still in the territory of compromises where you will find the Revox doing some things better and some things worse or equal.

I think in pure engineering terms they did the right thing - if it is designed to be a REPRODUCER - then the VTA is determined by the standard set by recording / cutting engineers at the lathe.
That standard is followed by cartridge makers - and the Turntables role is to provide a platform for that.

The fact that many audiophiles like to use their turntable as a type of equaliser by playing with VTA etc... would be completely antithetical to the purist engineering perspective that drove these designers. (in my opinion...)

On the other hand I don't think they were at all averse to improving the analogue circuits - and they used the best designers (and design principles) of the day... (eg: Matti Ottala for the amps)

Anyway I'm blathering.... and I'm (clearly) a fan

bye for now

David

boyerd001
02-05-2011, 08:36 PM
Some really nice comments from David.

I'm always skeptical by the excessive desire to adjust VTA - if you are familiar with Rega TTs you'll find that they provide NO VTA adjustment with stock factory units, including the $5k P9! There is a "fact sheet" by Roy Gandy (founder of Rega) that debunks VTA:

http://www.n.mackie.btinternet.co.uk/documents/regaonvta.html

Then you have Simon Yorke who has just introduced his Aeroarm (don't ask the price - if you have to you can't afford it):

http://www.recordplayer.com/en/turntable/aeroarm.html

The Aeroarm looks like a sibling of the Linatrack with its short pivot to stylus distance.

There is no such thing as the "Perfect" anything, and the Linatrack arm incorporated into the ReVox direct drive turntable is still amazing to me even to this day. I bought my first B790 in 1978 and have ridden the "wave" up and down ever since (count me as a fan also).

Dale

Pio1980
02-05-2011, 10:22 PM
Good comments David, thank you. The mod'ed Linatracks (I've heard of them) doubtless had stratospheric pricing. My Souther SLA-3 likewise has unusual short pivot-to-tip spacing (tho' nowhere as short as the Linatrack's cart carrier) and very low mass, lower than the Linatrack. I'm familiar with tuning VTA/VRA by ear tho' don't do it but for the average which while not optimum is acceptable for my purposes.

In spite of my respect for Roy Gandy for what he is doing bringing excellent products to market at their price point he is quite off the mark on the VTA thing in my experience if he claims it makes no audible difference as it definitely indeed does. Playing with VTA has nothing whatsoever to do with voicing a system, it has everything to do with getting the stylus to properly trace the groove as-cut for accurate reproduction. The cart mfgr's recommendations re leveling are generally close to optimum for the average run of LPs. That should do the deed for the Linatrack with a given compatible cart tho' I still think line contact stylii not the best choice for this TT.
Doing and maintaining "Perfect" is a PITA and the adversary of perfectly acceptable. I'm fine with perfectly acceptable and for those who've found it with a synergistic cartridge set-up, enjoy! I'm with you.

perryinva
02-06-2011, 02:34 AM
I've tried my B791 with the current V15-V-P mount with a Jico SAS, as well as with V15-III with elliptical and a Jico SAS, and also a Shure 1000e with elliptical. I have to say that I felt the V15V w/ SAS was easily the best combination, and that I did notice perhaps a bit more surface noise with the elliptical carts. I have 4 different TTs to compare, a Yamaha YP-D8, a Dual 1219, a Mitsubishi LT-20 and the B791. I only have 1 MC cart, and it's a HOMC, with a line stylus by VanDenHul, mounted on the YP-D8. I would say it's surface noise was slightly higher than the others listed, but that I also have some MA carts a 2002e and a 530MP, and both of those have more surface noise on "noisier" LPs. In general, as far as surface noise, I'd say the Revox is as quiet or quieter than the YP-D8 and LT-20, & definitely quieter than the Dual. It's been mentioned before that the Revox "drop" adjustment has to be set a bit lower than the manual recommends. As long as the rails are spotless, the cart is square and true to the radial, and VTA is close, it seems a seriously wonderful sounding table.

Naturally, I'm also a big Revox fan, (and an engineer) and while I would have to agree with most of what's beens said here regarding the engineering "impressiveness" design basis, that Revox seemed to love, their biggest fault has always been the use of what was at the time, "cutting edge" technology, to accomplish this, and much of that hasn't aged well. Their excessive use of 14066/4066, 1405X, 201, and 4136 quad chips in much of the B7XX and B2XX gear is an endless source of distortion and non linearity. (none in the TTs, obviously). There are WAY more electronics in a Linatrak than any other TT I've ever seen, even for a linear tracker. Thankfully, serviceability is so much easier than any other brand ever made, that upgrading is relatively easy. Good thing too, because their choice of Frako and Philips caps was their single worst mistake ever, and their traces lift easier on their PCBs than anyone elses I've seen.

SaSi
02-06-2011, 02:42 AM
I would comment that the electronics for the linatrack isnt' excessive. I would say that a Technics SL1300MkII has way more electronics even if the chip count is lower as it employs lots of custom VLSI chips. The Revox TTs utilize "discrete" vanilla flavor logic chips that - at least once - were available off the shelf on any decent electronics store.

Pio1980
02-06-2011, 03:10 AM
The Sony PS-X800 may take the prize for the busiest most fun filled base of any analogue TT. Absolutely daunting.
Was it worth it? Arguably the best integrated LT ever, they got almost everything right and then some.

Thnx to Professor Bizzt for the excellent pic.

perryinva
02-07-2011, 03:26 PM
I stand corrected! That's insane for a turntable! I'm not at all familiar with the PS-X800; I'll have to look it up sometime. SaSi is correct that Revox rarely used custom chips, thankfully, and of course it is pretty easily serviceable (except the motor Hall effect sensors, of course.) I do wish the Linatraks had adjustable feet, too.

steerpike2
02-07-2011, 05:18 PM
and of course it is pretty easily serviceable (except the motor Hall effect sensors, of course.) I do wish the Linatraks had adjustable feet, too.

Linear Hall sensors aren't dificult to get - they are mildly expensive. Honeywell's I think was the one I found that would be a most suitable replacement. Adjustment of phase balance after replacing could be a hassle - but a lot easier (maybe even trivial?) now, than in the 1970s - with things like digital storage 'scopes and computer based spectrum analysers being common now.

The feet are not adjustable but the height of each of the four spring columns on which the plinth is set, are each individually adjustable. Flat blade screwdriver from underneath I seem to recall.

perryinva
02-07-2011, 05:39 PM
Well, considering you have to lift it to adjust it, and then it can look cock-eyed in the plinth, it's a desperate adjustment at best, compared to simply screwing feet up and down. The old Duals have no adjustment either, so it's not that huge a deal. It doesn't seem to be as sensitive to level as a regular table, for sure.

Pio1980
02-07-2011, 06:35 PM
I stand corrected! That's insane for a turntable! I'm not at all familiar with the PS-X800; I'll have to look it up sometime. SaSi is correct that Revox rarely used custom chips, thankfully, and of course it is pretty easily serviceable (except the motor Hall effect sensors, of course.) I do wish the Linatraks had adjustable feet, too.

Then there's the Yamaha PX-1.
http://www.thevintageknob.org/YAMAHA/PX1/PX1.html

dlaloum
02-07-2011, 07:07 PM
The Sony PS-X800 may take the prize for the busiest most fun filled base of any analogue TT. Absolutely daunting.
Was it worth it? Arguably the best integrated LT ever, they got almost everything right and then some.

Thnx to Professor Bizzt for the excellent pic.

The design is obviously flawed.... I can see at least 2 bare patches without circuit board cover.....naked really! :beatnik:

MRL_Audio
03-12-2011, 10:23 AM
Well, I just read the entire thread. Couple of saga's in here. Did Robie ever get the table with the busted hall senors repaired and the table operational?

Yesterday I received a nice working B791. My first Revox. This is a nice add to my linear collection.

Revox B791
HK ST-7
Mitsubishi LT-5V
Technics SL-V5

Previous owner had it serviced by JMTech in TN before it was listed for sale. Also had him put a new Shure M97xE on the arm and calibrated properly. My only complaint is the feel of the base is a bit tacky. Understand this can be taken care of by stripping and repainting. For the time being I will live with the tackiness and attempt to keep dust and debris off of it. I was able to remove much of the debris yesterday by just using scotch tape and "peeling" the tape off of the base. When I get more time I will open her up and check caps etc. Great thread. Thanks to all the Revox AK'rs providing the knowledge base here.

Robie
03-12-2011, 11:04 AM
Markthefixer is still working on mine. Hoping it will eventually work.

guiller
04-04-2011, 04:32 PM
I'm thinking of a new cart for my B-795, and checking the Ortofon online matching tool ( http://www.ortofon.com/support/replacement-cartridges )I've got these sugestions:

Moving Magnet 2M Bronze
Moving Coil MC Vivo Blue
Moving Coil High Output X5-MC

I would be interested in the first two suggestions. Does anybody have a real-world experience with any of these on a B-795?

jt45
04-04-2011, 06:31 PM
Ive been using a Grado Black on my B790 for awhile with good results up until yesterday when it popped a resistor or the muting relay as someone suggested. In any event it shouldnt be too hard to fix since Ive already been inside of it during my first repairs a few months ago.

steerpike2
04-04-2011, 07:01 PM
A warning: you cannot put a 2M into a ReVox. The 2M has threaded body holes that need a bolt in from the top. This is impossible to do on the ReVox arm, unless you entirely disassemble the linatrack gantry before installing, then reassemble it after the cart is in. Big and risky job - not how ReVox intended the cartridge to be installed.

(It may be true of the other Ortofons - I haven't checked their mounting methods)

The OM20 / OM30 / OM40 are good matches for the ReVox.

dlaloum
04-04-2011, 08:43 PM
A warning: you cannot put a 2M into a ReVox. The 2M has threaded body holes that need a bolt in from the top. This is impossible to do on the ReVox arm, unless you entirely disassemble the linatrack gantry before installing, then reassemble it after the cart is in. Big and risky job - not how ReVox intended the cartridge to be installed.

(It may be true of the other Ortofons - I haven't checked their mounting methods)

The OM20 / OM30 / OM40 are good matches for the ReVox.

I beg to differ - I had an Empire MC1 mounted in the B795, it is threaded same as the 2M, and had to be mounted from the top.

This is a fiddly, painful, annoying and delicate operation.... it does not require dismantling the Gantry, as you can (only just!) get enough access from the top with the arm cover off - by using the sideways movement of the arm to provide just enough access to get a screw and driver in.

Achieving it will take MUCH time and patience.

So it is possible.... but definitely not recommended.

Needless to say, you really really really want to get the shimming (Height) right first time, and not have to dismount and remount....

My suggestion to you would be:

1) Go P-mount so you can swap cartridges easily and not worry (much) about shims/VTF/alignment once you initially get it aligned. (you can get Grado's, Ortofon OMP's and Ortofon X5-MCP - so most of your options are still there! Don't know whether the MC Vivo has been issued in a p-mount version)
2) Instead of the 2M bronze consider:
OM30 - Same price as Bronze (roughly) same needle and high quality cantilever. (or OMP30)
Digitrack 300SE - P-Mount Ortofon sub brand from the 80's - acording to my microscope images the stylus looks to be the same as the OM30 - half the price of the OM30/Bronze. (Digitrack SE stylus can also be fitted to OM bodies - but not OMP bodies - with very minor plastic cutting)
In compliance terms these are a good match for the Revox Cu=30/35


Bye for now and good luck

David

Robie
04-05-2011, 09:17 AM
Cartridges: FWIW, mine came with a Grado Signature 8MR. While it worked only briefly when I got it, I was surprised with the amount of bass it produced despite the warbling sound that started this thread. As I already have an 8MX I figure I'm familiar with the sound of this cartridge and various more modern Grados may be worth considering.

Status of my 795: As for the current status of my 795, I was contacted by a very generous fellow AK member who was parting out a 795. He offered me the motor and related assembly that may contain replacement Hall Sensors. It is in the process of being shipped now and any spare parts not used may be available for others in need in the future. More on this soon.

guiller
04-05-2011, 09:36 AM
Thanks for the carts suggestion: I've also read that people use AT440MLa or AT150MLX, which I would prefer over the Grado (I'm not inclined towards the "warm" sound). AT and Ortofon models may be more easily available locally. Did anybody here use any AT carts on the 795?

BTW, mine is performing very well now, but the cart I' ve mounted on it is too old and needs replacement.

dlaloum
04-05-2011, 09:50 AM
I have an AT150 and an AT440

Also p-mounts of the same stylus/generator family

Signet TK6 & Tk4
AT SLT96
Realistic (AT) RX1500

I am currently doing some tests on them.

For the revox, I am thinking one of the p-mount variations will do admirably, I picked them all up relatively cheaply without styli - and then purchased an AT440MLa for the stylus.... which nomadically moves from cartridge to cartridge as I try them out.


You can pick up the p-mount AT bodies on fleabay quite cheaply.... and then fit the stylus at the budget/performance level you want onto it.... from ATN102 (conical) through ATN120e eliptical, ATN440MLa Line Contact to ATN150MLx exotica.
The cartridge loading (resistance and capacitance) basically needs to match the stylus type and the cartridge inductance.... to which end I have been measuring and mapping out frequency response at various loads and capacitances for some of these cartridges. (so far the AT150, AT440 and TK6, at 60/300/420/535pf and 10/20/43/83ohm)

If you are seriously considering this family of carts, I can post up some of my F/R plots, which will help in tuning your setup.

bye for now

David

P.S. I am currently doing most of my testing on a JVC TT - I have a feeling the AT might be a touch lower compliance than ideal with the Revox. The Linatrak works best with cartridge having compliance of well over 20cu.
Mind you I was using an Empire/BenzMicro MC1 on there for years with a compliance of around 14cu

guiller
04-05-2011, 10:08 AM
Thanks a lot for your input: I still have to decide which new cart to buy, but the ATs are there in my short list, as well as the Ortofon models suggested by Steerpike2.

guiller
04-05-2011, 10:09 AM
The OM20 / OM30 / OM40 are good matches for the ReVox.

Many thanks for your input: I'm keeping them in my short list then!

steerpike2
04-05-2011, 05:19 PM
There is also the Shure M97XE - which some love and some hate.
I have an M97XE in one of my B795s. The other B795 is curently waiting for an OM20 or OM30 to arrive (I'll make the decision when the importer has the final prices)

I did have an AT412 in mine for a while, but it is rather massy and needed a counterweight fudge.

dlaloum
04-05-2011, 08:37 PM
Hi Steerpike...

An AT412 - isn't that an AT12Sa by another name/number?
Did you (do you) have both counterweights for the arm?
I do have an AT12Sa (actually an AT777 - but it is an AT12) - but I have not tried it in the Revox, it weighs less than the p-mount cartridges with adapters though, so I do not see why there should be an issue, as long as the lead counterweight is installed rather than the lighter brass one.

the M97xE has a distinctive "tone" - Frequency response becomes much more linear with a loading of around 68k ohm (according to Felix).

MM / MI cartridges are very sensitive to total capacitance and resistive load, and you can make one cartridge sound much like a different one by tweaking R & C... you can can also adjust R & C to achieve a flat frequency response.

I don't have a M97xE, but I do have a related Shure p-mount 1000e - to which I have fitted a Jico N97xE-SAS stylus.

The frequency response has a distinct Shure signature look, and the OM20/30 have a distinct Ortofon family look, as do the AT's - the differences between them can be reduced through proper loading (as they should be.... theoretically perfect cartridge should be identical.... ) but are always present.

bye for now

David

Robie
04-06-2011, 09:31 AM
The motor generously offered and mailed to me (well packed and all the way from Canada) by AK member taskerc, arrived safely yesterday. It came with the entire subboard that contains the Hall Sensors. If I'm lucky, at least a couple of the sensors will be functional but greatly appreciate his efforts regardless.

As taskerc, contacted me by PM out of the blue and offered the motor gratis, I'm feeling very fortunate and humbled, indeed. AK truly is a remarkable place and I'm lucky to be a very small part of it.

guiller
04-06-2011, 10:12 AM
The motor generously offered and mailed to me (well packed and all the way from Canada) by AK member taskerc, arrived safely yesterday. It came with the entire subboard that contains the Hall Sensors. If I'm lucky, at least a couple of the sensors will be functional but greatly appreciate his efforts regardless.

As taskerc, contacted me by PM out of the blue and offered the motor gratis, I'm feeling very fortunate and humbled, indeed. AK truly is a remarkable place and I'm lucky to be a very small part of it.

:thmbsp:

Robie
04-07-2011, 09:09 PM
I stopped by markthefixer's house today with the motor generously provided by AK member, taskerc. In the end, a simple motor swap finally solved the speed problem in my TT that lead to my original post as well as subsequent problems.

Previous efforts included replacing all of the tantalum caps and ICs on my motor control board, a diode (and today, the tantalum caps on my arm motion board). All of these efforts are documented in this thread.

In retrospect, I believe my problem may have originally been the motor board. However, in my uneducated fiddling I probably shorted and destroyed at least one of the Hall sensors in the motor assembly. (Why would someone with no knowledge of electronics (I'm a city planner) ever take on this task to begin with?)

Feels good to finally "win this one" though (particularly since I was in way over my head). With much patience and lots of help from a number of AK members (you know who you are, and in particular, steerpike2 and markthefixer), I am happy to report that my B 795 now plays records as it should.

I hope all those with B 795s continue to use this post to troubleshoot these cool TTs!

guiller
04-07-2011, 10:31 PM
I stopped by markthefixer's house today with the motor generously provided by AK member, taskerc. In the end, a simple motor swap finally solved the speed problem in my TT that lead to my original post as well as subsequent problems.



Congratulations!!! :thmbsp:

steerpike2
04-08-2011, 11:59 AM
An AT412 - isn't that an AT12Sa by another name/number?


Not an AT12. The AT412 is a metal-bodied TP4 type (circa 1990), with a TP4/½" adapter,

Did you (do you) have both counterweights for the arm?

I have one Revox brass, and one I made myself (steel).
The issue was that it increases the effective mass of the arm - which is probably appropriate since the compliance was not as high as I'd have liked.

MRL_Audio
04-08-2011, 01:27 PM
Moved to a new thread since it went sideways...

Robie
04-08-2011, 09:47 PM
First, congrats. MRL Audio. I hope you find the right cartridge.

I finally got my newly repaired 795 installed where I wanted it. Even though it's not known for a stellar phono section, my old McIntosh MA230 integrated has two phono inputs so I installed the Revox next to my Rotel RP1000 with Grado Signature 8MX. The 795 came with a slightly more modern Grado Signature 8MR so I thought a comparison might be in order.

I put several records on the 795 and while everything operated the way it should, the whole platter seemed to be moving up and down like a very warped record. I noticed it yesterday but in a more lighted room it was so evident it was the first thing my wife noticed when she walked in the room.

I bounced the top TT plate a bit thinking the suspension springs were not seated properly but it still rotated like the entire platter was warped relative to the top deck. I began to wonder whether we had incorrectly installed the replacement motor crooked relative to the top deck.

Finally I realized that the subplatter bearing shaft/spindle must be bent. I pulled the subplatter out of the bearing assembly and realized that the motor that taskerc sent me might have taken a hit somewhere along the way (probably in postage). A significant divot was missing from the bottom magnet ring.

After a few choice words and the nasty feeling of failure looming after over a year of wrestling with this TT, I finally I realized that I probably had an intact subplatter and bearing shaft from my original but malfunctioning motor assembly (with the bad Hall sensors). I simply substituted the subplatter from the original malfunctioning motor and now the TT platter (and original subplatter) rotates perfectly uniformly (level with no warp) in taskerc's replacement motor.

I need more time to compare the Revox to the Rotel and recognize that I have no idea what condition either Grado is in. As I think the stylus in both Grados are interchangeable, I may end up switching them to see if one is particularly worn.

I'll try to report more later.

radkrisdoc
04-09-2011, 04:29 AM
Been sick the past few days and we’re moving to a new place, have to set up internet, well, everything lol unpack, etc…..

I thought I'd start a new thread. But I think now that this thread has become such a good B795 thread, there is no better place.

I found a non-working B795 for sale in Chicago. I did some research on it and that made me want it. :drool: I posted on the AK pony express section for help as the seller was not comfortable shipping it. Then I got this idea! I pm’d Robie asking for help. Wow what a gentleman! He picked up the B795, paying for it himself…..driving 30 miles each way!

You have definitely shown me why AK is such a good place – cos there are good people here. To quote someone who could not have put it in a better way –

“I'm feeling very fortunate and humbled, indeed. AK truly is a remarkable place and I'm lucky to be a very small part of it.”

Thank you, Bob! Glad to see that your TT is finally working!

dlaloum
07-07-2011, 12:47 PM
A question for all you Revox users out there...

Has anyone used a peripheral ring clamp on a Revox?

I don't know whether one would fit.... I like the idea....

bye for now

David

guiller
07-07-2011, 06:50 PM
Been sick the past few days and we’re moving to a new place, have to set up internet, well, everything lol unpack, etc…..

I thought I'd start a new thread. But I think now that this thread has become such a good B795 thread, there is no better place.

I found a non-working B795 for sale in Chicago. I did some research on it and that made me want it. :drool: I posted on the AK pony express section for help as the seller was not comfortable shipping it. Then I got this idea! I pm’d Robie asking for help. Wow what a gentleman! He picked up the B795, paying for it himself…..driving 30 miles each way!

You have definitely shown me why AK is such a good place – cos there are good people here. To quote someone who could not have put it in a better way –

“I'm feeling very fortunate and humbled, indeed. AK truly is a remarkable place and I'm lucky to be a very small part of it.”

Thank you, Bob! Glad to see that your TT is finally working!

What a great story! :thmbsp:

steerpike2
07-08-2011, 08:02 AM
A question for all you Revox users out there...
Has anyone used a peripheral ring clamp on a Revox?
I don't know whether one would fit.... I like the idea....


I doubt it will fit. The platter is recessed into the chassis, with only about a 2mm gap around the periphery. The upper part of the platter that does extend above the motorboard is milled with a curve to accomodate fingers, and it is slightly smaller in diameter than an LP - not really conducive to a clamp anchoring on it.

dlaloum
07-08-2011, 08:16 AM
That was my own thinking - but I thought I would ask if anyone has found a clamp design that would fit.... I figure if it can be done, someone in this august fraternity will have done it!

bye for now

David

dlaloum
09-16-2011, 12:30 PM
Hi Folks

I was just reading the Revox Linatrack patents, and looking at the magnets that help keep the unipivot bearing stable.

Although damping is never mentioned (that I can find!) - it seems to me that this type of design is inherently damped.... all motion away from the neutral central position (as would be generated in an arm/cartridge resonance) would naturally be counteracted by the magnet - pulling the cartridge back to the central position.

It isn't really damping, in that it is not applying any friction to the motion, rather it is an inherently unstable unipivot system which is stabilised by magnetic force, so it is constantly and actively pulled to a central position at all times - and therefore there is active rather than passive force applied (albeit passively - using permanent magnets) to correct any vibrations.... effectively a damping force exists.

Is this right.... or is my mind just spinning cos its 2am and I should be asleep rather than thinking about magnets on really really short tonearms....

Associated with that question is the next one:
Given a Shure V15VP, p-mount cartridge, I have the option of fitting it with a p-mount SAS stylus (no brush) or a standard V15V SAS stylus (with brush).
The second option has the advantage of adding arm damping into the mix... but if the arm is already magnetically damped, am I in fact better off keeping the arm as light as possible (to minimise the inertia the magnets have to overcome and maximise their damping influence as a result) or adding the additional damping of the Shure brush/damper?

bye for now

David

jlb2
09-16-2011, 06:11 PM
Hi David,

I can't reply your first question, but I have used a V15P with the VN5MR SAS stylus on my B790, and made quite a few measurements with a test record. I found that the damping is noticeably improved with the brush lowered (lower infrasonic resonance level, although the frequency is not signicantly changed), but that it adds some pre-echo that I don't get on a different arm (Thorens TP16 MkIII to be more specific). My guess is that the ultra-lightweight arm of the Revox does not provide enough inertia and that the carbon fibers of the brush tend to pick up the previous grooves and transmit it by "shaking" the cartridge body. On the Revox, I tend to use this cartridge with the brush up except on warped discs for which the extra damping is a big plus. On the Thorens, I always lower the brush. In all three cases, the sound is great.

I have never heard of a P-mount SAS stylus (it is definitely not in the current Jico catalogue) and I don't have a working original VN5P, so I cannot comment on this configuration.

BTW I concur with steerpike on the clamp ring issue: the Revox has very little clearance both below the platter, above the platter and on the side, so none of the commercial rings I know of will fit, and a specific one is difficult to design at best (hardly anything to clamp on). As a matter of fact, even a centre clamp is hard to use on the Revox: the Michell I have is too thick for 180g pressings, and it is the thinnest I have been able to find.

dlaloum
09-16-2011, 10:54 PM
My guess is that the ultra-lightweight arm of the Revox does not provide enough inertia and that the carbon fibers of the brush tend to pick up the previous grooves and transmit it by "shaking" the cartridge body. On the Revox, I tend to use this cartridge with the brush up except on warped discs for which the extra damping is a big plus. On the Thorens, I always lower the brush. In all three cases, the sound is great.

I have never heard of a P-mount SAS stylus (it is definitely not in the current Jico catalogue) and I don't have a working original VN5P, so I cannot comment on this configuration.

BTW I concur with steerpike on the clamp ring issue: the Revox has very little clearance both below the platter, above the platter and on the side, so none of the commercial rings I know of will fit, and a specific one is difficult to design at best (hardly anything to clamp on). As a matter of fact, even a centre clamp is hard to use on the Revox: the Michell I have is too thick for 180g pressings, and it is the thinnest I have been able to find.

Thanks for the feedback...

One of the modifications that empire made to the 291, was increasing the strength of the magnets.... which effectively would increase the damping.... interesting? - I wonder what it would take to mod a linatrack in that way?

I have 3 V15 bodies: V15VP, V15V, and V15HR-P, for the first two only the V15VMR-SAS is available, for the third I could use either the V15VxMR-SAS, M97xE-SAS or the LPGear p-mount SAS http://www.lpgear.com/product/eSHN092ESAS.html.

Given that I custom load the cartridges, the difference in inductance between the V15V bodies and the V15HR is neither here nor there - either one can end up sounding the same....

Also the p-mount V15 setup may respond differently to the standard mount due to additional weight.... the cartridge itself is a bit heavier, and the P-mount adapter + shimm adds further mass - not sure whether that would be enough to make a noticeable difference though!

With regards to clamps, I use a 20+ year old BIB clamp that works perfectly with the Revox, the arm slides over it with plenty of room to spare... I have a few warped records where a peripheral clamp would be nice... which led me to research peripheral clamps, and many sing their praises... But probably not an option on the Revox.

Bye for now

David

jlb2
09-17-2011, 08:34 AM
Thanks for the feedback...

You are welcome.

Also the p-mount V15 setup may respond differently to the standard mount due to additional weight.... the cartridge itself is a bit heavier, and the P-mount adapter + shimm adds further mass - not sure whether that would be enough to make a noticeable difference though!
I really cannot say, as I only have the V15PSR. With the Jico stylus it is heavy indeed, 8-9 grams (just quoting from memory, I'd need to measure it again to be more specific). The P stylus is only 0.5 g lighter. OTOH the original mounting uses a 1mm shim, but you have to remove it with the SAS stylus (it is higher than the VN5P), which saves a whopping 0.2 g.

Incidentally, Revox used to balance the the turntables delivered with light cartridges by gluing a brass plate in the front end of the arm. This is something to take into consideration if your turntable originally came with, let's say, an Ortofon.

Oh, BTW I do have an element of reply to your question re. damping after all. My first Revox TT (an early B790 given by my aunt) came with a DL103, which is probably the worst possible match in theory - it is supposed to have a very sharp resonance peak at 15-20 Hz. Well, in reality it sounded and measured very decent, with some lf resonance but definitely not sharp, and certainly not as high as 20 Hz. Magnetic damping sounds like a very plausible explanation.

With regards to clamps, I use a 20+ year old BIB clamp that works perfectly with the Revox, the arm slides over it with plenty of room to spare...
Interesting info, thanks! I wish I had known that when it was made... I'll keep my eyes open in garage sales...

I have a few warped records where a peripheral clamp would be nice... which led me to research peripheral clamps, and many sing their praises... But probably not an option on the Revox.
That is the reason why I have the Thorens now: really warped records cannot be played well on the Revox. I have even seen one that didn't allow enough height for the arm! If you find a solution you will make many Revox owners happy :yes:

Pio1980
11-12-2011, 06:34 PM
I believe so.... can't remember which remote had which functions...

But I believe that the table is considered one of the "tape machines" (ie play forward and back work...)

I have been wanting this feature for my B795 for years.... there's a guy in Germany making an aftermarket plugin to do this for B795 (which had it as an external option) - and you can fit it internally!

But he charges 200euro for the circuit board - and then it needs to be fitted, and a hole drilled in the case for the IR receiver etc....

In any case I can't tell you the details as I have never had the opportunity to try it!

But if you want to swap your B291 for my B795......

The B200 series uses an LSI (proprietary?) on a single large single board instead of the array of standard chips on two much smaller boards as in the earlier B700 series, otherwise supposedly the same except for cosmetics. You lose the common chips advantage with the later ones.

Pio1980
11-19-2011, 09:37 AM
I've been re-reading this thread and am thinking that the gradual deformation that can occur with the composite baseplate under the weight of the platter may have warped the motor plate sufficiently to throw off the flux screw adjustment(s) for the hall sensors. While I am far from expert on these things I suspect the motor is much better off if it's remounted to correct parallelism (along with the gantry post) so that there is no rocking on the spacer washers before it's screwed down. The warpage was an issue for my B795's parallelism requiring correction tho' the motor plate remount showed no warp stress, this baseplate deformation issue has not been mentioned anywhere I can find. I believe it would be a common problem to all B795 with the composite baseplate, particularly those stored long-term with the suspension springs loaded with the platter on the spindle motor. The necessary correction is a fairly simple and logical if fiddly procedure.
See; http://www.audiokarma.org/forums/showpost.php?p=5155782&postcount=43

Pio1980
11-26-2011, 11:08 AM
I have found that liquid lubricants - oils, etc, on plastic cause 'stiction'. On plastic where grease is not approprate I always would only use graphite.

I think WD40 is the most vile stuff - suitable for garden swings, removing chewing gum & nought else. It tends to creep and infuse itself everywhere, doing more harm than good.

There are dry Teflon sprays and powders that I use for the H-K/RABCO ST-line of LT TTs after cleaning up with naphtha lighter fluid. Now that I'm in possession of a project B795 I can investigate the suitability there.

levlhed
12-08-2011, 10:58 PM
This thread is pretty epic.
I own a B795 now too but I need to get a new stylus before I can begin to pass judgement. It's got a very tired OMP10 on it but I'm thinking I'll pop the LP Gear Shibata Stylus 40 on it and see what happens...

Pio1980
12-08-2011, 11:47 PM
That'll beat heck out of remounting another cart. I also recommend replacing the old style 3-ring mat with one from a lower end Technics that is the same max thickness and appx diameter such as that used on the SL-Q200, KAB may have them. Also see; http://www.audiokarma.org/forums/showthread.php?p=5185196#post5185196
If yours has the composite baseplate check http://www.audiokarma.org/forums/showpost.php?p=5155782&postcount=43

dlaloum
12-08-2011, 11:53 PM
This thread is pretty epic.
I own a B795 now too but I need to get a new stylus before I can begin to pass judgement. It's got a very tired OMP10 on it but I'm thinking I'll pop the LP Gear Shibata Stylus 40 on it and see what happens...

Be interested to know what the resonant frequency is on that combo.. (LPGear Stylus40).... it would tell us what the compliance is on it!

levlhed
12-10-2011, 11:28 AM
I don't have a way to test the resonant freq, maybe after Santa visits there will be a new test record under the tree though...
I have the LP Gear Shibata Stylus 40 installed now and listening. It sounds much better than the cashed out Stylus 10, but I think I might need to go through some cart set up drills anyway. I literally just pulled the old stylus and popped the new one in (hoping) there'd be nothing else to do. I'm hearing some weirdness though, maybe mistracking with loud bass? Not sure yet what i'm hearing. I'm only on side one of the first LP, might just need a rekkid er two to get settled in....

unionista
02-25-2012, 09:31 PM
Hi all. I posted previously about the now-well-known motor speed issue on my B795. Well, I finally got around to bringing it to someone who knows what they are doing and hopefully I'll have it back in working order soon. I understand that it's getting a new motor PC board as well as some new caps. I'll post again with some details once I get the TT back.

On a related topic, has anyone successfully mounted any of the low-output MC cartridges on the the Revox TTs? How did they perform? Was the change worth it?

dlaloum
02-25-2012, 11:09 PM
The Revox is a relatively extreme beastie... ultra low mass, unipivot and linear tracking all in the one turntable!

What that means is that it requires a very high compliance cartridge to do its best.... and as a minimum a high compliance cartridge.

If the cartridge compliance is medium or low, you are pretty much wasting your time.

In the late 80's/early 90's Empire/Benz used to purchase the Revox TT and modify it to support their mid compliance MC's - this was a very successful modification...
They replaced the ultra light delrin tonearm, with a brass tonearm - instant mid mass arm! (to support the additional mass they used heavier duty magnets, and made the whole gantry more robust as well)

Most MC's are low or mid compliance - so not suitable...

Some exceptions are the upper range Denons (DL304 and DL-S1), and the Dynavector's.... these are all high but not very high compliance.

Honestly the best performance comes from cartridges with compliance of over 30cu....

bye for now

David

unionista
02-26-2012, 11:34 AM
Thanks for the quick reply, David.

I actually already have an Ortofon OM-30 but it's now very old. Maybe I'll just stick with that if it is the best choice anyway. I was looking for an upgrade path to better performance but I don't want to spend money just to make a lateral move. I do understand the compliance issue. That is why I bought the OM-30 long ago.

I've seen multiple mentions of ATs and Grados. Would any of them be better than the OM-30? Unlike some of the board members here, I don't have a lot of listening time with a wide range of TTs and cartridges.

dlaloum
02-26-2012, 05:24 PM
The early OM30's were 35cu - very high compliance

The current ones are 25cu

I don't think there is anything current out there that is higher compliance than that...

Current Grado's are all around 20cu
Current AT's are around 18cu

If you can still find an old Digitrac SE (300SE, 450SE)- they are (basically) a rebadged early OM30 - compliance 35cu - and a very good match for the Revox.

Older Audio Technicas (eg: AT155) were higher compliance too
The top ADC XLM series cartridges (XLM, XLMIII, SuperXLM, ZLM, Astrion) were also very high compliance.

I'm not saying the current Grado's and AT's will sound bad, just that the ones from the days when a top of the line arm was by default ultra low mass, will almost certainly sound better.

I ran an empire/benz MC1 on my Revox for a number of years... it led to my abandoning vinyl and moving to digital.... my experiments starting around 2 years ago with high to very high compliance cartridges in the Revox, turned things around. Brought the Revox back "on song"

bye for now

David

Pio1980
02-26-2012, 06:00 PM
Thanks for the quick reply, David.

I actually already have an Ortofon OM-30 but it's now very old. Maybe I'll just stick with that if it is the best choice anyway. I was looking for an upgrade path to better performance but I don't want to spend money just to make a lateral move. I do understand the compliance issue. That is why I bought the OM-30 long ago.

I've seen multiple mentions of ATs and Grados. Would any of them be better than the OM-30? Unlike some of the board members here, I don't have a lot of listening time with a wide range of TTs and cartridges.

I absolutely do NOT recommend Grados for the Linatrack. Once installed it would be VERY difficult to replace the stylus without risk of seriously damaging the carrier assembly. Much better an appropriate cart you can live with an easily replaceable stylus insert like the Digitrac, Shure ect, or a 'P' mount if you want to swap carts.

dlaloum
02-26-2012, 07:45 PM
The p-mount alternative has a couple of different advantages...

First it makes things easy for swapping entire cartridges (so a Grado can be mounted, and the whole cartridge is removed for changing the stylus... before plugging it back in)

Second:

the p-mount adapter instantly adds 1.5g of mass to the arm
The p-mount cartridges usually are a little heavier than their 1/2" mount equivalents - all p-mounts are 6g. The 1/2" V15V is 5g, as is the OM, the AT120/440 etc...
So using a p-mount, the effective total mass will rise from around 9g to 10g (including cartridge) to around 11.5 to 12.5g with the p-mount - making it slightly more suitable for the slightly lower compliance high compliance cartridges. (p-mounts have always been around 20 to 25cu for the most part)

I run the Digitrac (35cu) and the V15Vp-SAS in the p-mount adapter, and things are swimmingly happy...
I have a feeling that the digitrac mounted on the OM body with the weight removed (2.5g cartridge, effective total mass 6.5g!!) might perform better - but while I am comparing cartridges, the p-mount is very very handy

bye for now
David

guiller
02-26-2012, 08:31 PM
Hi David,

I read with interest your comments about the advantages of p-mounting of the Lineatrack arms. Would you please post a picture of the assembled cart+p-mounting+tonearm set?

unionista
02-26-2012, 09:08 PM
My memory of the P-mount setup when it was introduced was that it was kind of a "mid-fi" setup, not really considered high-end. Did this change through the years?

dlaloum
02-26-2012, 09:53 PM
Technics invented the p-mount, and initially launched it with primarily high end cartridges....

There were a number of distinctly high end p-mounts...

But by the early 90's the bottom end of the market adopted the p-mount as it was simple and consistent, so you ended up with a huge number of mediocre turntables being p-mounts.... and the high end ones being forgotten in the flood of mediocrity.

High end cartridges were available as p-mounts:
Shure V15V
Ortofon OM30 & OM40
Ortofon MC100 & MC200 (high end low output)
Technics EPCP100, EPCP205, EPC310 (MM & MC's)
Audio Technica AT152/142 (p-mount version of AT155, etc..)
etc...

Attached is a picture of my V15Vp (p-mount version of the V15V cartridge body) fitted with a Jico SAS VN5VMR stylus

You will also note that I have used nylon screws to attach the p-mount to the arm, as it saves 0.3g (every bit counts)

My p-mount cartridges include:
Shure V15Vp (also a range of other shure p-mounts V15HRP, 1000e, M105, Me75p)
Ortofon OMP20
Digitrac 300SE (Ortofon OMP30 equivalent )
Audio Technica AT142 (fitted with ATN152LP stylus)

My current jockey of choice riding the Linatrack steed is the V15Vp-SAS

bye for now

David

unionista
09-08-2012, 11:46 AM
Back in the spring, I brought my Revox to a Boston area shop for repairs. The owner made claims of being a Revox dealer back-in-the-day and being intimately familiar with my deck. As of today, I still don't have it in working order. After the first repair, I brought it home to hear an epic FAIL. I brought it back with the same problem. This guy never emails me unless I prod him first. I'm about ready to pull the plug on this venture and go in a different direction. He's clearly not really interested in this.

Pio1980
09-08-2012, 11:54 AM
It's hard to say whether it's a board problem or a motor Hall sensor problem. The easiest thing to start is to replace all the e'lytic caps as they are failure-prone in these. Some also recommend replacing the gumdrop Tantalum caps but I'd hold off until the e-caps are done and tested for play. Do NOT play with any of the trimpots on the boards without advice!

unionista
11-20-2012, 09:33 PM
I emailed the shop where I brought my 795 to see what was goin on. He said he had parts and would get back to me "in a few days". This time, he really did! The deck is supposedly fixed and I'm picking it up Friday. I'm trying not to get too excited as I've been let down before but it will be great to have my pride-and-joy back in the audio rack.:banana:

guiller
11-21-2012, 06:44 AM
My Revox B795 has been sitting there for some time and I'd like to get it into full operation. Its present situation is this:

It is working properly, but playback produces lots of record noise (friture). The cartridge seems to be not well set up. The cart is a Ortofon M 20 E, a very high compliance MM cart that could be a good match for the low effective mass arm of the Revox. However, I don' t have the mounting kit and although I used all the tips available on the net for cart mounting, none of them specifically mentioned this cart. The tracking force is set by using a digital scale. So, I am stuck between finding a mounting kit (very rare and expensive) or fiddle a bit with the cart position, spacers, and so on. I'll try to post a picture later today. Are there any tips or links suggested to tackle and solve this problem? I would even consider buying another cart, if that would solve this.

MRL_Audio
11-21-2012, 08:18 AM
dlaloum - I am interested in the lp clamp you have on this table. Can you provide the name, model and source? Like one for my B791. Thanks.

Robie
11-21-2012, 08:31 AM
As mine is still "fixed" and working, I sincerely hope all of you with problems can persevere. As vexing as this TT is, once working it is worth the headache involved in fixing it. The talent and knowledge here is amazing.

Pio1980
11-21-2012, 09:09 AM
Cart swaps are a Total PITA on these Linatracks, I highly recommend a 'P'-mount cart kit with an easily replaceable slip-in/slip-out stylus like a Shure or Ortofon (NOT Grado!) if a cart change is contemplated. No mounting kit required for 'P'-mount as it's max height without spacers. If you have the brass rather than lead counterweight the 'P'-mount may be too heavy for VTF adjustment range. In this case either sticking with what is in it if mounted properly and replacing the stylus (good luck with that without destroying the carrier if it's a Grado) is your choice. I like Grado carts BTW, just not a good option for these Linatrack TTs.

Pio1980
11-21-2012, 09:14 AM
My Revox B795 has been sitting there for some time and I'd like to get it into full operation. Its present situation is this:

It is working properly, but playback produces lots of record noise (friture). The cartridge seems to be not well set up. The cart is a Ortofon M 20 E, a very high compliance MM cart that could be a good match for the low effective mass arm of the Revox. However, I don' t have the mounting kit and although I used all the tips available on the net for cart mounting, none of them specifically mentioned this cart. The tracking force is set by using a digital scale. So, I am stuck between finding a mounting kit (very rare and expensive) or fiddle a bit with the cart position, spacers, and so on. I'll try to post a picture later today. Are there any tips or links suggested to tackle and solve this problem? I would even consider buying another cart, if that would solve this.

Use this as a guide for VTA; http://audiokarma.org/forums/attachment.php?attachmentid=248039&d=1294065391

guiller
11-21-2012, 11:32 AM
Use this as a guide for VTA; http://audiokarma.org/forums/attachment.php?attachmentid=248039&d=1294065391

Thanks for the picture: I remember to have used something like this when I was setting the cart up, but will check again anyway. I've forgotten all the details since time has elapsed. Perhaps I should try using a different cart, after all. I love the simplicity of operation of the Revox and would like to make it my daily use tt.

Pio1980
11-21-2012, 11:52 AM
Thanks for the picture: I remember to have used something like this when I was setting the cart up, but will check again anyway. I've forgotten all the details since time has elapsed. Perhaps I should try using a different cart, after all. I love the simplicity of operation of the Revox and would like to make it my daily use tt.
I think Dale Boyer originated the pic as a guide, very convenient. He's the go-to guru on matters ReVoX linatrack.

unionista
11-24-2012, 03:42 PM
Well, I picked up my Revox on Black Friday. The shop owner said he ran it for six hours (!) after servicing and it was operating perfectly. I just found the time today to set everything up and take it for a spin. EPIC FAIL- AGAIN! I don't know if this guy has a tin ear or if I'm totally being scammed. It's pretty frustrating as the TT works in every other way except for the previously-stated "warble" which sounds like a bad case of wow/flutter. My wallet is now $300 lighter and I'm pulling the plug on this venture. Maybe I'll try again in time, I don't know. I'm pretty disgusted right now.:sigh:

Pio1980
11-25-2012, 09:48 AM
This is not a typical result for this TT, explain to the guy that the fault still exists in spite of the work and expense.

unionista
11-25-2012, 11:42 AM
This is not a typical result for this TT, explain to the guy that the fault still exists in spite of the work and expense.

I'm not going back there. Either the guy is totally deaf or he's ripping me off. Either way, I'm out the money. I'll admit that I was glad to get the TT back without any signs that he damaged it further. I don't trust the guy. At this point, I would rather bring it to another stranger than back to a known failure. For the near term, it's back in the factory box and back in the closet. Right now, I need to get something else with the long-term goal, still, of getting the Revox running again.

MRL_Audio
11-25-2012, 12:08 PM
I don't think you should let the guy get away with this. He should be forced to finish the repair or refund you the money you spent to date. Also was curious if you gave it a test run before you left his shop the last time? Was it working then or not tested? Just curious and good luck. Been there a time or two. Finally found someone I can trust and have stuck with him.

unionista
11-25-2012, 05:40 PM
I don't think you should let the guy get away with this. He should be forced to finish the repair or refund you the money you spent to date. Also was curious if you gave it a test run before you left his shop the last time? Was it working then or not tested? Just curious and good luck. Been there a time or two. Finally found someone I can trust and have stuck with him.

Both times that I picked up the TT in his shop, the TT was broken down, packed in the original box and taped up upon my arrival. In fact, just like I had packed it myself! Hmmm....

Pio1980
11-25-2012, 07:06 PM
What will you be using in the meantime?

unionista
11-26-2012, 05:46 AM
What will you be using in the meantime?

IDK. I may buy something inexpensive, maybe the Denon DP-300 or the ProJect Debut Carbon. These are hardly a replacement for the Revox, I know. The Rega RP3 looks pretty attractive at its price point. I don't want to spend so much that it would be a waste to relegate the new TT to "2nd string" status if and when the Revox returns. OTOH, I don't want to buy a piece of crap that I'll be stuck with if the Revox never returns. In any case, I'm not in a rush to make a decision, especially with the holidays coming up.

Pio1980
11-26-2012, 08:35 AM
What cart is in the Linatrack?

steerpike2
11-26-2012, 10:27 AM
EPIC FAIL- AGAIN! I don't know if this guy has a tin ear or if I'm totally being scammed. It's pretty frustrating as the TT works in every other way except for the previously-stated "warble" which sounds like a bad case of wow/flutter.

What are your talents? Maybe it would be better to try doing some work on it yourself?

unionista
11-26-2012, 07:07 PM
What are your talents? Maybe it would be better to try doing some work on it yourself?

The thought has crossed my mind. I have zero experience with TTs but, OTOH, I have absolutely no fear of failure!:D I've tackled bigger projects. That's probably what I'll end up doing so get ready for a barrage of questions!:scratch2:

unionista
11-26-2012, 07:09 PM
what cart is in the linatrack?

om-30

Pio1980
11-26-2012, 11:54 PM
om-30

I've had its cousin, an O'fon Digitrac 200 NE 'Tombstone' in a B795, not bad. It doesn't sound bad in a Technics SL-7 LT either.

Pio1980
11-26-2012, 11:56 PM
The thought has crossed my mind. I have zero experience with TTs but, OTOH, I have absolutely no fear of failure!:D I've tackled bigger projects. That's probably what I'll end up doing so get ready for a barrage of questions!:scratch2:

As you may surmise from this thread the starting point for a just-found/acquired Linatrack is to replace all of the electrolytic capacitors and usually the Tantalum caps as well. Mine ran fine without replacing the Tant's.

perryinva
11-27-2012, 12:40 AM
Replacing all the electrolytic caps solved a speed instability issue on one of my 791s. Piece of cake. I did the tant's too, but only because I was already there. There is only like 4 or so, of them in the 791. Except for the Nextel paint, they are really awesome tables once set up well. I love mine.

unionista
11-28-2012, 06:56 PM
Did anybody catch that custom-finish Linatrack (don't remember which one) that someone was selling on ebay? I seem to remember that the seller was asking for an obscene amount of money for it. I wonder if it ever sold?

Pio1980
11-28-2012, 07:10 PM
I doubt it, I have no idea what that was supposed to be about.

steerpike2
11-30-2012, 06:10 PM
There was a really badly sprayed green B291. Bad, bad, bad paint job, even going over the rubber grommets, etc. Should have earned maybe 20% of the price of an untouched B291, due to all the re-coating it would have required.

As for your faulty one.... is the wow very regular? Or random?
Very regular wow may be caused by the failure of one phase on fthe motor - it is a 2 phase motor (not 3 phase).
If so, it could be an open circuit in the motor, a failed transistor, a failed op-amp, or.... we hope not.. a failed Hall sensor.

And check it has the right platter - the B790 has a 1.1kg platter, the B795 and all others a 2.2kg platter - but they look identical.

unionista
11-30-2012, 07:37 PM
As for your faulty one.... is the wow very regular? Or random?
Very regular wow may be caused by the failure of one phase on fthe motor - it is a 2 phase motor (not 3 phase).
If so, it could be an open circuit in the motor, a failed transistor, a failed op-amp, or.... we hope not.. a failed Hall sensor.

And check it has the right platter - the B790 has a 1.1kg platter, the B795 and all others a 2.2kg platter - but they look identical.

I bought this TT brand new. I assume it has the correct platter from the factory. Operation was flawless for two decades until I attempted to use it after a long period of non-use.

I characterize the problem as a "warble" in the music. Maybe this is a bad case of wow/flutter? Interestingly, the LED speed indicator shows a "locked" speed in spite of the plainly audible error. This "warble", as I call it, is continual- it colors the music each and every second of play. It occurs with every LP I've tried.

steerpike2
12-01-2012, 06:43 AM
I bought this TT brand new. I assume it has the correct platter from the factory. Operation was flawless for two decades until I attempted to use it after a long period of non-use.

I characterize the problem as a "warble" in the music. Maybe this is a bad case of wow/flutter? Interestingly, the LED speed indicator shows a "locked" speed in spite of the plainly audible error. This "warble", as I call it, is continual- it colors the music each and every second of play. It occurs with every LP I've tried.

OK, I though MAYBE an incompetent service agent might have switched platters.
Constant warble is a good sign - it points away from faulty motor or Hall ICs.
The PLL-lock light has a built-in delay, so if the PLL isn't unlocked for a long time, it doesn't show an error. This is evidently a 'fast' PLL oscillation about the setpoint.
First area I'd look at is the tacho head amplifier - its IC and the electrolytic capacitors around it. If you have access to an oscilloscope (a cheap 10MHz one is fine), that will tell you everything you need to know about all the circuitry and how it is working.

It could still be a power supply issue - a 60Hz half-wave ripple on the supply to the motor or PLL might sound like your description - though I'd have guessed the heavy platter mass would damp that to inaudible levels. (just a guess though).

Pio1980
12-01-2012, 09:35 AM
OK, I though MAYBE an incompetent service agent might have switched platters.
Constant warble is a good sign - it points away from faulty motor or Hall ICs.
The PLL-lock light has a built-in delay, so if the PLL isn't unlocked for a long time, it doesn't show an error. This is evidently a 'fast' PLL oscillation about the setpoint.
First area I'd look at is the tacho head amplifier - its IC and the electrolytic capacitors around it. If you have access to an oscilloscope (a cheap 10MHz one is fine), that will tell you everything you need to know about all the circuitry and how it is working.

It could still be a power supply issue - a 60Hz half-wave ripple on the supply to the motor or PLL might sound like your description - though I'd have guessed the heavy platter mass would damp that to inaudible levels. (just a guess though).

Corrupted PS rails due to deteriorated reservoir/filter and bypass elyt'icaps is a good possibility and also with bad elyt'icaps causing problems elsewhere. If the guy who owes you a full refund did not replace them all wholesale then it must be done before any other analytical work is attempted to eliminate the usual suspects first, low-hanging fruit and all that.

unionista
12-01-2012, 08:49 PM
I'll be tearing the thing apart soon. I want to see exactly what, if anything, was done. Skeptical doesn't even begin to describe how I feel about this guy's work. Really, I wonder if he even took it out of the box.:no:

Pio1980
12-02-2012, 03:07 AM
Good luck and keep posting, we've got your back on this.

Robie
12-02-2012, 08:37 AM
As the OP and chief cheerleader here, a big thanks to all who keep sharing your knowledge with others on this thread. That's all. Carry on.

Highwaystar
12-02-2012, 11:54 PM
Did anybody catch that custom-finish Linatrack (don't remember which one) that someone was selling on ebay? I seem to remember that the seller was asking for an obscene amount of money for it. I wonder if it ever sold?There's a B-790 on ebay if that's the one you're talking about that hasn't sold yet. The owner wants $804 plus $150 shipping. I was wondering if that was a good price for this particular turntable.
Karl

Pio1980
12-03-2012, 01:25 AM
No, another one. Regardless, that one would have to be professionally fully overhauled by an acknowledged expert to be worth anything near that IMO.

unionista
12-09-2012, 08:59 PM
OK, finally, free time AND ambition coincided! I opened up my 795 to see what the tech did to it and, more importantly, what he DIDN'T do. This is what I found...

394983
A view of the tonearm control board and motor control board.

394985
I assume this is the power supply for the motor current. These are the capacitors to replace?

394986
Power supply transformer.

394987
I have no idea what this is but it is part of the power supply.

394988
The motor bearing. The scratches tell me the tech DID go in there.

394989
Looks like a fresh seal on the motor board mounting screws. I guess the tech was in there, too.

I'm guessing that the caps in the second pic are the ones to replace. Anything else?

Pio1980
12-10-2012, 12:13 AM
The big blue and gold axial tubular capacitors should have been replaced, not sure if the smaller ones were done but if German/European origin, not done. The power transformer needs be confirmed rewired for 120-130 Volts, the "I-have-no-idea" bit is a power input filter and probably OK as-is. He 'may' have fooled with the brass thrust bearing cup at the bottom of the motor to comp for a worn/depressed thrust plate, hope he used an oscilloscope to do it if he did. Better he didn't tho' he may have invested the entire repair just fooling with the motor itself, hard for me to tell just from the pix. Hopefully not tho he still owes you a total refund for failing to find and fix the original symptom fault.

unionista
12-10-2012, 05:55 AM
He 'may' have fooled with the brass thrust bearing cup at the bottom of the motor to comp for a worn/depressed thrust plate, hope he used an oscilloscope to do it if he did.

The tech DID mention using a 'scope to check that as he was warning me not to try it myself. Why the use of the 'scope? Is the bearing cap installed to a certain torque and the 'scope measures the effect of physical "drag" of the thrust bearing on the resulting motor speed?

Pio1980
12-10-2012, 08:34 AM
The distancing of the rotor magnet to the Hall Effect device position sensors is critical for proper smooth operation of the motor and that brass cup affects this, there are also two tweaking screws (not the 'sealed' ones in your pic) for the individual distancing of each Hall sensor that should never be casually changed. These adjustments are pretty much a total PITA to perform even with the proper gear BTW. He may have earned something for verifying them but I would have also verified the cdx of the spindle thrust plate and spindle shaft end before doing so as replacement affects those adjustments, depending on how conscientious he was, we'd like to think that his procedure at least confirmed to proper operation of the Hall sensor portion of the motor circuit. Replacing the el'ytic caps routinely wasn't done or necessary when these TTs were au courant as their ESR ratings had not yet aged out as is common later on with these euro-sourced caps, the Japanese el'yticaps seem to age more gracefully. He may not be aware of this tho' o'scoping the PS rails and other critical points would have called attention to these problems.

Regardless, from here all the el'yticaps need be carefully and properly changed out. Do not fool with the trim-pots on the boards unless they are carefully marked for wash-clean wiping in order to return the adjustment to the same exact point. The disc thingies on the power supply board are surge devices and are fine as-is.

unionista
12-10-2012, 05:22 PM
OK, so it appears that I have to find and order (5) capacitors. Anything else while I'm at it?

Pio1980
12-10-2012, 06:35 PM
What make are the smaller stand-up el'ytics?

unionista
12-10-2012, 07:22 PM
What make are the smaller stand-up el'ytics?

All of the small caps where I can see the name are marked "Phillips".

Pio1980
12-10-2012, 08:30 PM
All of the small caps where I can see the name are marked "Phillips".
Replace those too then, they are also suspect. We'll hold off on the gumdrop Tantalums for now unless you just want to do them all for reliability sake. There is no guarantee all this will fix it but these are the most likely 'usual suspects' on these ReVoX TTs.

unionista
12-10-2012, 09:00 PM
Replace those too then, they are also suspect. We'll hold off on the gumdrop Tantalums for now unless you just want to do them all for reliability sake. There is no guarantee all this will fix it but these are the most likely 'usual suspects' on these ReVoX TTs.

Acknowledged. Time for me to get to work. Thanks for your help. I'll post again when I have something to report.