Altec 807-8A drivers

[cabinover]

I bought a pair of these quite a while ago along with some 511Bs to play with. As I've mentioned to Bowtie one of these was way down in volume so Tom mentioned checking DCR and should that be good to swap diaphragms.

Having never taken a driver apart I was apprehensive but managed to do so sans incident. The diaphragms are labeled 21545. Both measured out at 5.7 Ohms. Haven't had a minute to see just yet if the low volume follows the diaphragm but will tonight.

On another thread I noticed mention of losing the loading cap (which I take to be the plastic cover on the diaphragm?) and installing felt to the inside of the rear cap. Is this still a good idea?

I know, I know, e-wave and all but I want to play in this sandbox for a while.:yes:

Bob

 

[Russellc]

I bought a pair of these quite a while ago along with some 511Bs to play with. As I've mentioned to Bowtie one of these was way down in volume so Tom mentioned checking DCR and should that be good to swap diaphragms.

Having never taken a driver apart I was apprehensive but managed to do so sans incident. The diaphragms are labeled 21545. Both measured out at 5.7 Ohms. Haven't had a minute to see just yet if the low volume follows the diaphragm but will tonight.

On another thread I noticed mention of losing the loading cap (which I take to be the plastic cover on the diaphragm?) and installing felt to the inside of the rear cap. Is this still a good idea?

I know, I know, e-wave and all but I want to play in this sandbox for a while.:yes:

Bob

When you remove the loading cap, you will need shorter screws. Without that thing like a spacer, the long screws will bottom out before getting tight.
Lord knows I've played with Altecs, and still do, but those smaller drivers are more high frequency limited than 802 or 902 versions.

As to Ewave, it is FAR superior to the 807 in terms of high frequency extension. It also only costs 44 bucks or so for the driver, less than a diapragm replacement for Altec.



Russellc

 

[Zilch]

Do we have cause for believing that removing the loading cap is going to improve the performance of 807-8A?

What are they, 806-8A with loading cap and Pascalite diaphragm?

Is there also an end cap? With felt?

E'Wave's Seleniums are threaded throat, whereas 511B is bolt-on, also available.

The bolt-on version could ultimately be used with the E'Waveguide and a $5 throat adapter, but vice-versa, i.e., thread-on driver with a bolt-on throat adapter to 511B is not such a good option....

 

[doucanoe]

I know, I know, e-wave and all but I want to play in this sandbox for a while.:yes:

Bob

Man, that was he quickest move from "No e-wave conversation please" to full blown e-wave conversation I have seen here yet.

RC

 

[mhardy6647]

If you tire of those 511Bs... I'll meet you in Newburyport again, anytime

 

[Zilch]

Stock diaphragm for 807-8A is Symbiotik #34726, apparently.

I do not find #21545 anywhere on the list:

http://alteclansingunofficial.nlenet.net/Diavc.html

NOTE 5 - ALL older Altec drivers must use a 288/291 or 800/900 Series Conversion Kit in order to be retrofitted with ANY Altec Lansing Diaphragm manufactured after 1983. Every Altec Lansing driver manufactured before 1983 will require one of these kits the first time a post-1983 diaphragm is installed in it.

NOTE 13 - Symbiotik® diaphragms are no longer available. If high power handling is required, and excellent HF frequency response is also needed, use diaphragm #26420 (8 ohms). For superior HF reproduction, use diaphragm #34647 (8 ohms).

From the Altec Forum:

The original diaphragm in an 808-8A was model# 21545, it's the old style with screw-on lugs, the later model was a 34726, Dave.

Greets!802, 804, 806 are alum. loaded for various studio/HIFI apps while 807, 808 are Symbiotik loaded for PA/MI high power apps. The 30904 will tame the latter a bunch, but will never make it suitable for studio/HIFI.If this isn't good enough extension, then you can add a by-pass cap around the 30904 to 'lift up' the extreme HF: http://www.lansingheritage.org/images/altec/specs/pro-systems/9846-8a/page02.jpg

The old '75 list shows that # used in both 807s and 808s exclusively, and all in MI/PA systems, so they'd be Symbiotiks. 908s started with Symbiotics also, so that diaphragm evidently was in production post-AlNiCo. Since no Symbioteks have been made for a long time (being surpassed by the current versions), the choices now are aluminum or Pascalite (stock from GPA), or aluminum or titanium (aftermarket from ???). They've fallen from favor, but they weren't terrible. More importantly, is their condition, if they saw regular commercial usage as intended, the surrounds may be compromised just from regular, long-term use. Play 'em. The proof's in the pudding, and the choice is simple. If they sound fine to you, enjoy, if not, ante up. For the best advice which to buy for your system nowdays, ask Bill when you call to order some.

Almost forgot- the newer diapragms require a kit because connections to the diaphragm have changed. Great Plains carries these also.

 

[Russellc]

Do we have cause for believing that removing the loading cap is going to improve the performance of 807-8A?

What are they, 806-8A with loading cap and Pascalite diaphragm?

Is there also an end cap? With felt?

E'Wave's Seleniums are threaded throat, whereas 511B is bolt-on, also available.

The bolt-on version could ultimately be used with the E'Waveguide and a $5 throat adapter, but vice-versa, i.e., thread-on driver with a bolt-on throat adapter to 511B is not such a good option....

It improves the performance of the 802 and 902 units...while the loading caps helped with power handling, like the Symbiotic drivers, they dont help with high frequency extension. In home hifi use, I find a little more air on top with the loading caps removed. I've not tried it with the smaller Altec drivers ( 806 and 807, etc.) as they are more limited on HF than the other models.

He said he had backs to put felt in, ( which is done if you remove the caps )
if not they can be obtained from great plaines audio. I dont begrudge anyone playing with Altec....Like I said I do. A big honking pair of A7s downstairs.

Russellc

 

[Russellc]

Do we have cause for believing that removing the loading cap is going to improve the performance of 807-8A?

What are they, 806-8A with loading cap and Pascalite diaphragm?

Is there also an end cap? With felt?

E'Wave's Seleniums are threaded throat, whereas 511B is bolt-on, also available.

The bolt-on version could ultimately be used with the E'Waveguide and a $5 throat adapter, but vice-versa, i.e., thread-on driver with a bolt-on throat adapter to 511B is not such a good option....

Whats wrong with using a thread on with an adapter to bolt on? I'm not saying there isnt anything wrong, I just wondered why? I used them to connect my 2425H to both 511B and 2344?

Russellc

 

[Russellc]

Here's the little bugger in question:

Russellc

 

[Zilch]

Whats wrong with using a thread on with an adapter to bolt on? I'm not saying there isnt anything wrong, I just wondered why? I used them to connect my 2425H to both 511B and 2344?

It's fine if the screen on the threaded "snoot" ends up flush with the bolting surface, as with the adapter standard on 2426H, for example. Some adapters create an additional cavity there.

However, the snoot itself becomes a throat extension in normal installations. There's nothing similar occurring when the bolt-on Selenium is used directly mounted to the 811/511 flange. I found measurable differences using the two geometries here:

http://audiokarma.org/forums/showthread.php?p=1629046#post1629046

 

[Steve O]

I bought a pair of these quite a while ago along with some 511Bs to play with. As I've mentioned to Bowtie one of these was way down in volume so Tom mentioned checking DCR and should that be good to swap diaphragms.

Having never taken a driver apart I was apprehensive but managed to do so sans incident. The diaphragms are labeled 21545. Both measured out at 5.7 Ohms. Haven't had a minute to see just yet if the low volume follows the diaphragm but will tonight.

On another thread I noticed mention of losing the loading cap (which I take to be the plastic cover on the diaphragm?) and installing felt to the inside of the rear cap. Is this still a good idea?
I know, I know, e-wave and all but I want to play in this sandbox for a while.:yes:

Bob

Jeff Markwart recently examined in an objective manner, the issue of "to load or not to load" for a 604E HF driver (close enough for government work). My interpretation of his conclusions is that removing the caps and adding felt or whatever to the inside covers may not be the no-brainer improvement everybody thinks it is. You need to consider your xover point, slope and desired max SPL. You can read for yourself here>>>Altec Compression Driver Rear Loading Caps

I've removed the caps and added felt to a pair of 802 somethings on 511s I use in my basement high eff system. 12dB/800Hz xovers with mods for improved HF response are used. I found the differences to be mostly minor at the SPLs I play them at but I haven't put the caps back either. I'd be interested in your interpretation of Jeff's conclusions.

 

[cabinover]

I knew it wouldn't take long for the thread to turn e-wavy

I did pull the loading caps and installed felt along with some nice brass screws last night. Did it make a difference to my ears? I don't know...maybe. It's hard to tell and I still can't lay my hands on my SPL meter. At this point it really doesn't matter though, I'm just playing around.


SteveO, this setup isn't going to have large SPLs either. From what I gathered reading Jeff's writeup is that it really doesn't matter with lower SPL levels. I could be way off base though.

 

[Russellc]

Jeff Markwart recently examined in an objective manner, the issue of "to load or not to load" for a 604E HF driver (close enough for government work). My interpretation of his conclusions is that removing the caps and adding felt or whatever to the inside covers may not be the no-brainer improvement everybody thinks it is. You need to consider your xover point, slope and desired max SPL. You can read for yourself here>>>Altec Compression Driver Rear Loading Caps

I've removed the caps and added felt to a pair of 802 somethings on 511s I use in my basement high eff system. 12dB/800Hz xovers with mods for improved HF response are used. I found the differences to be mostly minor at the SPLs I play them at but I haven't put the caps back either. I'd be interested in your interpretation of Jeff's conclusions.

I'm in the same boat you are in, same driver (basically, 802 8G here...) same crossover point, etc. Like you, I found minor differences on the high end, both with 902 and 802, and while minor, these can use the help on top. In the home setup, I dont think there is any problem, I've played them at high volumes ( for home use) and never blown a diapragm. For "PA" or other similar uses, I'm sure there could be a reliability problem.

As to it being a "no brainer" like you said, its a minor change, but I found it pleasant. This topic was beat around on the Altec forum with similar comments. I believe, if I remember correctly we determined it was altec who claimed more high end, but with 500 hz crossover points and resulting blown diapragms with "pro" use, loading caps and symbiotic type diapraghms came into use. towards the end, the Pascalite material was used and the claim there is that it has the same power handling ability as the symbiotic, and the extension of the non symbiotic diapraghms.

Either way, it has been demonstrated by Zilch and others that:

1.) The smaller altec drivers, 806 etc do not have the extension of the 802 and 902 versions, and

2.) there are more modern compression drivers ( BMS, B&C, and Selenium) that outperform them in terms of flat response and extension.

I still like them,
Russellc

 

[Russellc]

I knew it wouldn't take long for the thread to turn e-wavy

I did pull the loading caps and installed felt along with some nice brass screws last night. Did it make a difference to my ears? I don't know...maybe. It's hard to tell and I still can't lay my hands on my SPL meter. At this point it really doesn't matter though, I'm just playing around.


SteveO, this setup isn't going to have large SPLs either. From what I gathered reading Jeff's writeup is that it really doesn't matter with lower SPL levels. I could be way off base though.

I dont know if what I'm hearing is measurable. Perhaps its not more extension, but more air from the the diapraghm being less constrained...does this result in more extension, or something else, or is it the same and I'm imagining it? Does more "shimmer = more extension? Seems like it would, but I dont know, I hear a difference I find, Like the author of the article did, " that it is good advice" and I will continue to do it for home use.

Russellc

 

[Andyman]

I knew it wouldn't take long for the thread to turn e-wavy

Yeah, but it can't be helped as it such a nice, dare I say????, upgrade for so little money, it really needs to be considered. I actually funded the purchase of all the parts, crossovers included, I used from selling the 806s alone; the money from the 811Bs and Altec crossovers was gravy...:yes:

I've documented it over in the E-Wave and in some Valencia threads, but I tried LOTS of stuff with the 806/811Bs in my Valencias including add on tweeters (3 types, thanks dnewman04 & Kegger!!), model 19 crossovers, Seleniums on the 811Bs w/ 3 different crossovers (Valencia , M19, EWave), and even 806s on the EWaves, and liked the E-Wave the best.

Now, that's not to say the Altecs didn't sound nice with that sweet midrange. I actually had a stock version with an add on tweeter set up on one channel and one with the EWave system mounted on an adapter board on the other and was able to roll the balance so I could compare a mono recording. I had to tweak the volume to balance the sound for the Valencia midrange hump, but after 5 minutes or so, the sound out of either speaker was pleasing, and very listenable. It really took some hard listening back and forth to make the choices, so I won't be touting "night and day" differences, but I made my choice on what I like.

Actually, I wound up selling the Valencias piecemeal and built a scratch EWave based upon the JBL LE14.

I'd see if someone has a spare set of Seleniums and an adapter to bolt on your horns to play with. They probably won't go as low as you need, but they'll certainly have more highs. At $30 a pop, it's really a pretty cheap tweak that pays quite nice dividends.

 

[Zilch]

I knew it wouldn't take long for the thread to turn e-wavy

I'm trying to squelch that a bit here, and encourage you to make these discoveries and determinations via "playing around" yourself.

However, I'm also pointing out that, if you want to actually get down to it, and if one of your diaphragms has "issues," you will have to, as Bfish stated, "Ante up" to the tune of $200+, very likely, and frankly, as others are also telling you, 807s converted to 806s aren't worth that investment, in my view.

As Andy points out, there are "Believers" out there who will pay good money for those, perhaps enough (depending upon how stalwart) to substantially offset the cost of a pair of BMS drivers, even.... :yes:

 

[cabinover]

I hear ya and appreciate the anti-derailing. I've had these for a couple years now and just not had the time to play around with them, not that I do now either but...

I don't believe after shifting things around that I have diaphragm or magnet issues. The only issue I have is in my head apparently. Seems I hear better out of my right ear than my left. I swapped everything only to find out nothing had changed. Duhh...

It's been brought to my attention that it could be allergies and I have been very stuffed up lately so maybe with luck that's what it is.

I eventually will do the e-wave thing, already have a pair of LAs that need to be refoamed then just maybe. Appreciate the thoughts of all you guys though and I realize you want to help :yes:

Maybe I'll sell these off, make my e-waves, keep the 604s and still have Altecs kicking around! Hmmm...I may be on to something.

 

[Zilch]

I'd hang on to the 511Bs 'til I had a chance to work them with decent drivers.

If a pair of 511E's came my way, they'd likely be keepers here, bored out to 1.5".... :yes:

 

[Lecta414]

any ideas if this is a 1967 or 1977 ? and what possibilities for the diaphram model?

 

[bowtie427ss]

any ideas if this is a 1967 or 1977 ?

Green says '67.

By '77 they were all charcoal/gray.

The only way to be sure of a diaphragm number is to pull it and look.