A8 VOTT (Restoration Help)

[capicva]

Hello,

I recently acquired a pair of A8's from a local seller. They were pretty banged up, but I got them at a very low price. They were sold "as-is" and one of the 15" drivers was "not working" but at the price it was well worth the risk.

I thought they were newer, but when removing the back cover of the speaker with the non-sounding driver I found a green framed 416-Z (which I have read here is a factory installed 416-A) and an 806A compression driver on a 32 90° horn. Luckily the woofer was disconnected from the crossover and worked fine when reconnected.

Upon closer inspection I realized the "working" speaker had a slightly different 15" driver and when I removed the back panel, found that it had been replaced with a black frame Lansing 515B (which is dated with crayon on the cone 12-23-88). I am assuming the old 416-Z on this speaker was damaged and replaced with the 515B.

So, given that these drivers have different specs: will they be able to work as a pair?

The enclosures have some delamination in the bottom plywood panel (apparently stored at floor level in a very humid place) and the pots on the attenuator seem to be rusted in place. I have no problem with changing the panels and wiring new crossovers from components, but will it be worth it given the low frequency driver mismatch?

Please take into account I am in Costa Rica, so I cannot simply snatch a matching driver off eBay (customs and shipping would probably duplicate the cost).

Thanks in advance for any and all help.

[Earl K]

I don't see the difference between the 416z and the 515b as a show stopper.

Here's a comparison of these two woofers ( the pics originate from a Japanese blogger who noted his repair efforts while employed at a HiEnd restoration/repair shop ).

http://www.audioheritage.org/photopost/data//500/515b_10026681266.jpg

http://www.audioheritage.org/photopost/data//500/416-8A_10051566476.jpg

One can see that these two woofer types ( at least at this point in their life-cycle ) actually have pretty similar response characteristics.

HF: You'll want to consider adding a tweeter to your horn/driver combo since it'll have very weak HF response above 4 or 5K.

Here's a Zilch graph that hi-lights your HF challenge;

http://www.audioheritage.org/photopost/data//500/Zilch_806_on_811_511B_.PNG

As seen in the pic one can get HF response all the way out to 20K ( if you have the luxury of cutting the combos mid-range response by @ 15 db ).

One could go that route by biamping ( & then passively filtering the mids downwards to flatten the curve ), then finally turning up the gain on the HF amp to restore balance to the woofer section.

:)

[sonofagun]

Some pics of should prove interesting. :blink:

[capicva]

sonofagun: http://www.photon.colectico.org/index.php?/category/2 (just a few snatched with my phone that day)

Earl K: thanks for those graphs, I guess this kinda motivates me to try to keep them original and perform a straight rescue mission. I just remembered my brother has a dbx measuring mic and I could just do a sweep on these two and actually see how far apart they are (duh).

[Drugolf]

sonofagun: http://www.photon.colectico.org/index.php?/category/2 (just a few snatched with my phone that day)

Earl K: thanks for those graphs, I guess this kinda motivates me to try to keep them original and perform a straight rescue mission. I just remembered my brother has a dbx measuring mic and I could just do a sweep on these two and actually see how far apart they are (duh).

Hey Capicva.

I am in the midst of an A8 rebuild myself. It looks like yours are plywood. Mine are pressboard so I am rebuilding cabinets entirely. With yours, depending on that moisture damage on the bottom could easily be patched up with some bondo and repainted nicely. You could go with the more typical Altec Grey color as well at that point....or whatever might be your flavor of choice.

Are your 32 horns plastic or metal?

[capicva]

Hey Capicva.

I am in the midst of an A8 rebuild myself. It looks like yours are plywood. Mine are pressboard so I am rebuilding cabinets entirely. With yours, depending on that moisture damage on the bottom could easily be patched up with some bondo and repainted nicely. You could go with the more typical Altec Grey color as well at that point....or whatever might be your flavor of choice.

Are your 32 horns plastic or metal?


Indeed. The sides aren't bad, mainly the top and bottom panels have delamination. I think one top can be fixed, but both bottoms require a change.

These are metal horns.

[capicva]

An eternity later...

[DerekTheGreat]

Better late than never! A lot of these threads are left with no conclusion..

[Mr. Widget]

An eternity later...Nice!

Are you happy with the results? They look cool.


Widget

[1audiohack]

An eternity later...

Welcome back!

Barry.

[capicva]

So far, so good. That is the original plywood with a little watered down black dye and a lighter gray than the original A8.I redid the crossover with the schematics available in this forum.I am currently running moOde on a RPi and I'm trying to get RoomEQWizard running for measuring and setting up some filters in CamillaDSP.Can't complain. :D