Altec 808-8A horns restoration - can these be saved?

[Dvanamps]

Hi all,

I recently acquired a pair of Altec 808-8A drivers with N809-8A crossovers from an old railway clear out up north. Needless to say they looked pretty rough but I felt they might be worth a gamble for 100 bucks. In fact “rough” might be a slight understatement, they appear as though they were left outdoors on a railway platform for about 40 years!!

The initial place was to restore and repaint the horns and replace the diaphragms on the drivers (assumed busted) followed by a health check on the crossovers. These drivers would then form the basis of a larger project to build a pair of Altec A7 speakers + cabinets from scratch.

So they arrived yesterday and already I feel I’m in over my head slightly. The drivers were completely rusted shut and I even managed to snap a pole on one when trying to remove from the horn itself. As suspected the diaphragms were completely corroded and crumbled on sight! It seems as if they have fused with the driver magnet itself?

I have attached images of both the drivers and the crossovers and would like to hand it over to the professionals to help me decide whether these units are worth saving or not? Or even more, can they be saved at all? If so where to start? What’s the best method of stripping these magnets down safely, cleaning them up and starting again with some clean replacement parts?

Same applies for the crossovers, they look like they have been worked by a sparky trying to problem solve up on a ladder one cold winters night. Worth saving? They seem more straight forward to rebuild but may require a full strip down and start again I imagine?

Before proceeding to the photographs I will warn you, some people may find these scenes offensive, please proceed with caution. That said, I still feel deep down it would be a magical moment to hear these old birds tweet once again.


Your thoughts and consideration are very much appreciated, thanks in advance.

Dvan

 

[winters860]

I’d think about starting by soaking the drivers in an enzymatic rust remover. It might very well take off the paint, but we’re talking about a salvage operation. I’ve seen worse brought back to life.

 

[Mr Boochie]

Those are very nice capacitors!

Good luck with your resto!

 

[Nyjblbob]

Hi all,

I recently acquired a pair of Altec 808-8A drivers with N809-8A crossovers from an old railway clear out up north. Needless to say they looked pretty rough but I felt they might be worth a gamble for 100 bucks. In fact “rough” might be a slight understatement, they appear as though they were left outdoors on a railway platform for about 40 years!!

The initial place was to restore and repaint the horns and replace the diaphragms on the drivers (assumed busted) followed by a health check on the crossovers. These drivers would then form the basis of a larger project to build a pair of Altec A7 speakers + cabinets from scratch.

So they arrived yesterday and already I feel I’m in over my head slightly. The drivers were completely rusted shut and I even managed to snap a pole on one when trying to remove from the horn itself. As suspected the diaphragms were completely corroded and crumbled on sight! It seems as if they have fused with the driver magnet itself?

I have attached images of both the drivers and the crossovers and would like to hand it over to the professionals to help me decide whether these units are worth saving or not? Or even more, can they be saved at all? If so where to start? What’s the best method of stripping these magnets down safely, cleaning them up and starting again with some clean replacement parts?

Same applies for the crossovers, they look like they have been worked by a sparky trying to problem solve up on a ladder one cold winters night. Worth saving? They seem more straight forward to rebuild but may require a full strip down and start again I imagine?

Before proceeding to the photographs I will warn you, some people may find these scenes offensive, please proceed with caution. That said, I still feel deep down it would be a magical moment to hear these old birds tweet once again.


Your thoughts and consideration are very much appreciated, thanks in advance.

Dvan

IMHO the only thing salvageable are the horns, X-overs,
and on the drivers, Just the back caps and Loading caps.
I doubt the driver's Voice coil gap is still good.
Meaning the Whole Motor assembly is Gone.
Good luck with them

 

[Dvanamps]

I’d think about starting by soaking the drivers in an enzymatic rust remover. It might very well take off the paint, but we’re talking about a salvage operation. I’ve seen worse brought back to life.

Thanks for this suggestion, I was thinking about Evapo-rust or possibly Citric acid to soak these but not sure on which route to take just yet.

 

[Dvanamps]

Those are very nice capacitors!

Good luck with your resto!

View attachment 2941468

Yes agreed! Any tips for removing old silicone per chance? haha

 

[Dvanamps]

IMHO the only thing salvageable are the horns, X-overs,
and on the drivers, Just the back caps and Loading caps.
I doubt the driver's Voice coil gap is still good.
Meaning the Whole Motor assembly is Gone.
Good luck with them

I know its a tall ask for sure! I will try posting any updates in this regard as and when. Thanks for your interest and advice!

 

[Mr Boochie]

Yes agreed! Any tips for removing old silicone per chance? haha

Screwdriver and elbow grease. Once out of the main blob, you'll need to peel the layers off. Hopefully preserving the labels.

I like using Teflon or shrink insulation. And maybe a touch of silicone sealer or glue gun, if vibration is an issue keeping the caps stationary.

 

[bowtie427ss]

Those are very nice capacitors!

They should go well with those 1/4 inch phone jacks.

IMHO the only thing salvageable are the horns, X-overs,
and on the drivers, Just the back caps and Loading caps.
I doubt the driver's Voice coil gap is still good.

Agree. The motors are doorstops.

When all is said and done, the gap will be wider than stock, and almost certainly irregular. A proper restoration will include new polepieces and front plates. Cost prohibitive would be an understatement.

For economic sound reinforcement, or another outdoor paging/PA application they'd probably be satisfactory. The problem with doing that is that sooner(likely) or later they will be injected into an uninformed hifi enthusiast resulting in an expensive lesson and long lasting bad taste.

For hifi i'd not waste my time and energy. We're not dealing with uncommon drivers here.

Start with a workable pair.

 

[Dvanamps]

They should go well with those 1/4 inch phone jacks.


Agree. The motors are doorstops.

When all is said and done, the gap will be wider than stock, and almost certainly irregular. A proper restoration will include new polepieces and front plates. Cost prohibitive would be an understatement.

For economic sound reinforcement, or another outdoor paging/PA application they'd probably be satisfactory. The problem with doing that is that sooner(likely) or later they will be injected into an uninformed hifi enthusiast resulting in an expensive lesson and long lasting bad taste.

For hifi i'd not waste my time and energy. We're not dealing with uncommon drivers here.

Start with a workable pair.

Thanks for this, I will try take these comments on board. I think at this stage I’m more in the mind-set of just getting these drivers to sound again as an exercise in understanding/practise more than anything else.

Is it even possible to strip one of these down completely ? and if so has anyone here ever heard of it being done? Can the top plate be removed from the magnetic structure?

I attached another photo of the phasing plug in its current form for reference.

 

[bowtie427ss]

Is it even possible to strip one of these down completely ? and if so has anyone here ever heard of it being done? Can the top plate be removed from the magnetic structure?

It's all possible.

That doesn't mean it'll be in any way, practical.

ANY disassembly will require that the motor is magnetically re-charged before it's going to work again. That means shipping to one of a shrinking handful of speaker techs who offer this service, and back.

 

[elitopus]

I think it’s just Great Plains and Upland that offer remag these days.

Yeah the 802/808 motors can be had cheap if you buy them without diaphragms. Usually a good pair of diaphragms (Radian or GPA) cost more than the motors.

I wouldn’t mess with any Chinese diaphragms. They make sound and that’s it.

I agree with restore the horns/xovers and look for some different HF drivers. I mean you could clean those up for funsies….

 

[Mr Boochie]

I think it’s just Great Plains and Upland that offer remag these days.

Yeah the 802/808 motors can be had cheap if you buy them without diaphragms. Usually a good pair of diaphragms (Radian or GPA) cost more than the motors.

I wouldn’t mess with any Chinese diaphragms. They make sound and that’s it.

I agree with restore the horns/xovers and look for some different HF drivers. I mean you could clean those up for funsies….

I had all my speakers re-mag'ed at Speaker Repair Pros, in Garden Grove, CA.

 

[EarlK]

CNET's Comparison of Liquid Rust-Removers

EarlK

 

[elitopus]

I had all my speakers re-mag'ed at Speaker Repair Pros, in Garden Grove, CA.

So then 3 shops still do remags. That’s all the places in the US I think.

 

[Mr Boochie]

So then 3 shops still do remags. That’s all the places in the US I think.

I had my 136A (alnico magnets) remag'ed last, 2018.

 

[elitopus]

I still have a bunch of AlNiCo drivers, but I’ve been buying more ferrite drivers nowadays. For the future

 

[toddalin]

Speaker Repair Pros got their equipment from Orange County Speakers when they went out of business and is run by a former OCS employee.

 

[Mr Boochie]

Speaker Repair Pros got their equipment from Orange County Speakers when they went out of business and is run by a former OCS employee.

The original tech's son.

 

[kcdonahue]

Wow! You have your work cut out for you, but still worthy of a good try to save the drivers. The crossovers should be much easier focusing on the replacement of parts and dealing with corrosion.

I've had good luck with restoring rusty drivers/motors using evaporust, elbow grease, compressed air and lots of well sized foam q-tips to clear the magnetic gap. The drivers pictured below were stored upright for years with the horns attached and were filled with scum and exposed to the elements (full of moisture and low PH materials in a leaky barn). From the pictures, these drivers were not as bad as yours, but after soaking in evaporust and multiple cleanings my comparative measurements using the same diaphragms were very consistent compared with two pairs of "reference" drivers, one pair remagged by GPA and the other a very clean pair that still had very nice light diaphragms.

Also, the evaporust that I used had seen a lot of time restoring gas tanks and other automotive bits before being used here. I filtered the solution past a neo magnet and through a coffee filter before soaking them just in case. I wish I took a picture before I started, but the entire driver was filled along with the horn throat.