Altec 802-8g (model 19)

[BRAD OURSO]

Hi,
I have a pair of Altec Model Nineteen's with the 802-8gs in them. The diaphragms
were replaced with Great Plains diaphragms. As I understand, the original
802-8g diaphragms were slightly thinner than
any other high frequency aluminum diaphragm
that Altec had ever produced. (Which gave them a superior high frequency response.) I also understand that Great Plains replacement diaphragm is not specifically for the 802-8G............it also fits others...so does this mean that it is not exactly what they were from the factory? Reason being, I find that my refitted 802-8gs don't have quite the response from 17-20KHz that my friends original speakers do.

[Tom Brennan]

Brad---yeah, 802-Gs and early 902s supposedly had a lighter diaphragm. If you search here you'll find a thread about the subject, a fella named Shawn Fogg started the thread.

Did you blow your original diaphragms? And if so did you have the drivers remagnetized? It's said that blown Alnico drivers often have the magnets weakened in the process and that a weak magnet will result in rolled off highs.

[Todd W. White]

There was a very thin diaphragm for the 288-G and 802-G that Altec made for a very little while, as it was unable, as I recall, to bear up under the abuse most people gave it.

All small and large format diaphragms made by Altec (and now GPA) fit the drivers that use the same mounting ring, voice coil, etc. In other words, you can put the Symbiotik diaphragm in an 802, and it becomes an 808, an aluminum one in a 299, and it becomes a 288, a Pascalite one in an 808 and it becomes, in effect, a 909, etc. These parts were purposefully interchangeable.

That said, the ultra-thin diaphragms were not commercially viable for Altec, so they opted for the slightly heavier ones, followed by the 909 (Pascalite) types.

As for listening quality, it is possible for me to hear the difference between the different diaphragms, but I'm picky and am listening for the difference. Most people never notice it, as the difference is way up in the stratosphere where the typical listener is unable to hear, anyway.

[gamalot]

I think the lighter ones you refer to are # 23744 which can be found printed on the inner side of the VC.
The new ones from GPA are most likely 34647s.

I have 802-8Gs with each of the above and there is a slight difference in sound but very, very slight.
On the flip side, the new diaphragms are much stronger where the leads attach and not nearly as prone to lead failure. I also believe the original ones are now close to 30 years old and aluminum might tend to get brittle over time making them less responsive and weaker in high volume systems.
What Tom said about the magnets is a bleief I also agree with and always send the drivers to GPA when new frams are necessary. They are remagnetized while there and it is included in the fram price. Good insurance IMO.
I would also add that if your XOs have all the original caps in them, you might look at replacing these as they are known to have a tendency to go out of spec over time and hard usage.
Given a choice between New old stock 23744s and the new 34647s from GPA I would certainly take the new ones as I feel they are the better choice in the long run. The old ones do appear at auction from time to time and I do chuckle when I see them bring a higher price then nice new ones. To each his own!

Gary

[BRAD OURSO]

Well........i did a side by side comparison with
my friends old 802-8gs and my new (great plains)
diaphragms...... and the difference was astounding. All of your posts have confirmed what I was afraid of............I still have perfect hearing, and I really enjoy hearing the ultra high frequencies that the originals can reproduce with such accuracy........It is my understanding that this was one of the reasons altec engineers used the 802-8Gs in the Nineteens and it is why they sounded more Hi-Fi than any of the VOTTs. It is a real shame that you can't get the original replacments anymore. I guess I'll have to buy the old ones on eBay and hope they're the real deal.

[gamalot]

Hold on just a minute Brad!
Your description of the difference being "Astounding" tells me something else is wrong. I can side by side my 802-8Gs here with both diaphragms and the difference is very, very slight.
First get your drivers remagged and see if this is the problem. Then if you fell up to it, switch one of your friends horns and drivers into your boxes and XOs.
I am willing to bet you need magnetizing or your crossover caps are out of spec.
Like Todd said, very few here could even hear a difference between the two as long as all other components are up to spec. If your magnets are weak so too will your sound be. If your caps are leaking or way out of spec then your HF is the first to go. New OLD frams won't fix either.
Also, are your drivers really 802-8Gs?
Here is what they will look like with the frams off.


Gary

[BRAD OURSO]

My alnico magnets were remagnatized, and my crossover is most definately in spec, as it was checked at Great Plains. And, of course my drivers are Really 802-8gs.......they came with the model 19's and I have friends with identical 802-8gs, also know the original owner as he gave them to me. I guess I was a little dramatic with astounding.....but I can tell you that to ME, a slight difference is a problem, and I am not happy with the performance of these frams. You know, a "slight difference" is a relative term, and I think a big factor in determining the level of differnce depends upon how good one's own hearing is at the time of the test. Most people over 30 have lost a significant amount of hearing in the freq range that Altec intended the 802-8g's to reproduce accurately. They would not have designed them that way if the difference was not significant. I really feel and "hear" that the originals sound significantly better. Just my opinion.

[gamalot]

Here is where the numbers are on the originals.
You might want to check to see what your friends diaphragms are and start searching the auctions for a set of the identicle ones you seem to like.

I can't hear much difference but then, I am old.

Gary

[LICORNE]

So your high frequencies are not loud enough.

Could be a slight difference in your L Pads compared to your friend's model.

That could result in a DB loss.

There are some super Caps out there also.

Convergence

.............................

[RonSSS]

Jim Dickenson told me about the special diaphrams in the 802-8g's many years ago. He told me not to blow them up, as they were no longer available. I still have the letter he wrote me.....way before the internet was a *****le in Gores eye.

I still have those drivers, in pristine condition. I bought them new in a pair of A7-X's in 1977.

That said......

I measured the freq response of the 8G's compared to a pair of 902-8As, on the same horn, and the same conditions. There was no difference.
My setup was a TEK 7L5 spectrum analyzer, tracking generator and a calibrated microphone.

To my ears, the 902-8A's are superior sounding....even though they are ceramic magnets.

However, I haven't hooked up the -8Gs to compare to in quite some time. Maybe I ought to try that soon.

BTW...I remove the bug screens....they limit the HF response.

Try some 902-8As....they are wonderful. Jim told me that way back when, I believe he was correct.

Ron