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Vacuum tube based R2R - call for votes

L

LinuxGuru

Well-Known Member
I am being (in some degree) addicted to tubes :music:, probably due to warm memories from the time of colorful childhood back in USSR :thmbsp:

I am thinking about purchasing tube-based R2R device. Anyone have such? What is your impression of sound recording/reproduction quality compared to top solid-state AKAI or Revox? Are you using them or keep just for collection?

Thanks in advance.
 
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I have a Akai M8 is extremely good condition a one owner machine with very little time on it and I know from reciepts it was maintained regularly while it was in use.

And it is a very nice sounding machine both running on it's own amps and when running through my Scott 233 amp. As to a direct compareson to my Pioneer RT-707 or TEAC 1230 I would say it's warmer with a slightly narrower frequency response then the RT-707 or TEAC A-1230.
 
The best Pro-sumer tube-based R2R ever made was the Revox G36. It is the only compact three-head-three-motor direct drive design, with 10.5" reel capability desing that I am aware of. The last time that I checked, it was still possible to get new heads for these machines too.

Ampex's F44, and some of the tube Tandbergs were three head machines that are supposed to sound pretty good too, but they were 1 motor, 7" designs with lots of belts.

Akai/Roberts made a number of two-head, one motor models. But if you want extended high-frequency response, then you would be much better off with one of the three head models.

There are a number of large pro models too, but I have ommitted these due to size, weight, and track format.
 
goldear said:
The best Pro-sumer tube-based R2R ever made was the Revox G36. It is the only compact three-head-three-motor direct drive design, with 10.5" reel capability desing that I am aware of. The last time that I checked, it was still possible to get new heads for these machines too.
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Thanks a lot! Does this Revox G36 has permalloy or glass-ferrite heads? Did you bought it from USA or Europe?
 
LinuxGuru said:
Thanks a lot! Does this Revox G36 has permalloy or glass-ferrite heads? Did you bought it from USA or Europe?
Click to expand...
I believe the G36s have permaloy heads, or at least some variant of permaloy for the pole pieces. Ferrite heads hadn't been invented yet back then. Some of the older G36 heads actually feature a composite construction of some sort. But I wouldn't let that turn you off, as the Revox heads have always been known for very-good longevity.
 
The best Pro-sumer tube-based R2R ever made was the Revox G36
Click to expand...

I saw a G36 for sale a few days ago for $4000, I kid you not!
If replacing heads, they wouldn't put original G36 heads into one now, mine had new heads put in by Revox and they are the same as go into the B77.
(Original G36 heads are cylindrical with connections at the bottom; new ReVox heads are square with rounded front, and connections at the back.)

The bronze pushbutton switch contacts on the G36 sometimes break. It's a fair bit of work, but I converted mines pushbutton bank to microswitches + relays.

The actual tape transport on the G36 is REALLY solid.
 
steerpike2 said:
I saw a G36 for sale a few days ago for $4000, I kid you not!
If replacing heads, they wouldn't put original G36 heads into one now, mine had new heads put in by Revox and they are the same as go into the B77.
(Original G36 heads are cylindrical with connections at the bottom; new ReVox heads are square with rounded front, and connections at the back.)

The bronze pushbutton switch contacts on the G36 sometimes break. It's a fair bit of work, but I converted mines pushbutton bank to microswitches + relays.

The actual tape transport on the G36 is REALLY solid.
Click to expand...
$4k?!? That's crazy.

Actually the new all-metal heads that they sell for the G36 look like B77 Heads, but they do not have the same specs. They are much higher impedance.

And I agree, the transport is built like a tank.
 
They are much higher impedance
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Ah yes, good thing you pointed that omission of mine out.
What i really wanted to say was that you can tell if a machine has the original or the improved heads very easily by looking at the shape.

I must pull out mine - i havent used it in about 20 years.
 
There is no true 4-track 354 factory made. There is a 300 4 track (1/2" tape only). The 350 transport is 1/4" only. Some 300 transports may have been paired with 354 electronics. Not my favorite electronics due to heat and difficulty in servicing and aligning the electronics. The best consumer format 1/4 or 1/2 track tube deck is definitely the ReVox G36. Next best would be an Ampex F44 FineLine or a 960. The Tandberg 62 and 64 are excellent if you want a tube 7" machine as well. Magnecord and Crown made some fine tube decks if you want an alternative.
 
The 354 electronics pack two channels into the same amount of rack space (4 spaces) occupied by a single channel of the 300/350/351 series electronics.

354amp.jpg


The standard three-head block such as was used on the 300/350/351 was standard on the 354 as well, but one could order a custom 4 head arrangement if they so desired. This block was the same as used on the PR 10 series of machines.

Here's my 354's transport, showing its 4 head block. Left to right, they are: half track two channel erase; half track two channel record; quarter track two channel reproduce; half track two channel reproduce.

ampex15ips.jpg


ampexheads.jpg


The lever in the middle selects which repro head feeds the electronics. Down is for half track, up for quarter track.
 
Jay,

Your 4-track play head on your 354 was added after it was purchased. Very nice conversion job. Ampex officially offered the 1/4 track play head as an option when the AG 440 was introduced in 1967. Nice machine! I just like the 351 electronics better when maintenance or repairs must be done. Your 354 electronics made their debut on the infamous PR 10 introduced in 1961.
 
Thanks! I bought the 354 in 1988 from its original owner, and from I understood, he'd ordered it with this head stack. He used it in his disc cutting system, with a Neumann AM 32 lathe fitted with a Westrex 3D stereo head. I think one reason he wanted the quarter track repro head was so he could offer people a means of easily transferring their home-recorded quarter track tapes straight to lacquers (as this was 45 years ago now).

If you ever get your hands on a 354 amp, here's a quick/cheap way of significantly improving the recording quality:

Schem1.jpg


On each 6AW8A, add a 470K resistor from after the .47 µf capacitor (1C12, 1C13) back to the grid of the pentode section, pin 7. This adds some much-needed negative feedback. For added stability, I also added a 100K resistor from each pentode grid to ground.

Here's what this deck sounded like in its stock state, in 1967:

http://www.youtube.com/watch?v=vDmLBkbPdQk

That's on Scotch 201 tape, at 7 1/2 ips. Engineered by the guy I bought the deck from!
 
I would say the G36 Revox would be a good choice.....I have a Ampex 354 and 350's though.....a work in progress.....I want to build a 350 1/2" 4 track...have all the parts....just need to find the time. The Ampex tube electronics are classic though....
 
My dad once had an Ampex 1100 and it was great. It was auto-reverse, using the old Ampex method of putting a reversing signal on the tape. Being auto-reverse, it also had this funky auto threading takeup reel that can be removed.
There's one being auctioned right now, but it's missing one of the covers over the takeup side.
(no affiliation... only mentioning for informational purposes)
 
Earlier, I wrote:
I saw a G36 for sale a few days ago for $4000, I kid you not!
Click to expand...

I lied! It was 4000 British POUNDS!

And the auction has ended at..... 6468 pounds!

That's US$ 9079 at todays exchange rate!

For a Revox G36, can you believe it? Willi Studer must be doing the macarena in his grave.
 
steerpike2 said:
Earlier, I wrote:


I lied! It was 4000 British POUNDS!

And the auction has ended at..... 6468 pounds!

That's US$ 9079 at todays exchange rate!

For a Revox G36, can you believe it? Willi Studer must be doing the macarena in his grave.
Click to expand...

Heck....I saw two go on fleebay for less than 800 IIRC.....just proves fools and their money soon part company.....9000 smackers OMG.

Update.....A G36 went for 450 bucks on March 1......I think someone is........
 
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Jay Pemberton said:
Thanks! I bought the 354 in 1988 from its original owner, and from I understood, he'd ordered it with this head stack. He used it in his disc cutting system, with a Neumann AM 32 lathe fitted with a Westrex 3D stereo head. I think one reason he wanted the quarter track repro head was so he could offer people a means of easily transferring their home-recorded quarter track tapes straight to lacquers (as this was 45 years ago now).
Click to expand...

Thanks for feedback! Do you have full schematic for this Ampex model?
 
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