New owner of Beveridge Electrostatics!

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lbenveniste

Member
Joined 2021
cvanc said:
You have 2SW-2; I have 2SW-1, ours are 99.5% identical. So here's some comments and suggestions that might be helpful.

The metal chassis with the fan is a VERY HIGH VOLTAGE amplifier that wants to kill you if you work on it and don't know what you're doing. Further, it will hurt the whole time you're dying. If you feel you might not be experienced enough to take on this project, please please do not do so. Get them to someone who can help you with that and has the necessary high voltage tools.

The amplifiers are notoriously unreliable and often need to be completely rebuilt. If they have been unused for decades don't even turn them on. Just get them to a good tech as your step one. Repairs here are almost always expensive, and almost always needed. You saw the rebuild I had to do - I didn't do it for fun, it was needed to make them work at all.

The cabinets contain three identical panels. You have the 1st generation panels. The bent pieces in the front are actually a 'lens' according to the company and mine are as warped was yours. It's unattractive but not in your top twenty problems. Ignore it.

What IS a problem is decades of storage with no grill foam across the mouth of the lens. Dust, dirt and bugs get in and contaminate the front surface of the panels. In order to clean the front of the panels you have to remove them from the cabinet. Let me know if that's something you'd like to take on and we'll talk about the particulars.

The company was very small and the entire production run was a couple hundred pair. As far as I know there's only about twenty pair still running in the world.

When these run they are simply astonishing. But it's like having an old sports car in the garage - they will make you suffer for your enjoyment ":^)

Best wishes.
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cvanc,
Thank you so much for the reply and the information. It really is with great sadness that I do believe I've decided to sell them instead of taking this on. I just dont have the time, space, or tools for a successful project. Would you be able to point me to where I might find a starting price for these? Any info is very much appreciated.
 
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cvanc

Member
Joined 2015
Noooooooo!

Don't give up yet. Honest, get 'em fixed. They will change your audio life.

I was laying it on thick 'cuz this amp is just an awful first project for someone. But... so what? "Who does the work" isn't really the next topic here - it's "what work needs to be done"?

Here's what I suggest: Start that thread! Much can be learned from thorough visual inspection so post a ton of nice clear photos. I'll chime in. Mine have blown up so many times I'm a bit of an expert. Unfortunately ":^)

Also, find someone with a tube tester that can test 36KD6. Be careful removing them as they sometimes break at the base.

Ask all the questions you need about getting the amps off the cabinets and opened up. There's a couple other 2 series users here and it is a freakin small club world wide.

(Post a thread here asking for local help, maybe?)
 
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cvanc

Member
Joined 2015
I spent a little time on cosmetics on my pair (which were basically a 'barn find' when I got them). I've oiled the veneer and finally glued on new foam.

Beveridge electrostatics.jpg
 
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Lampie519

Lampie519

Member
Joined 2006
Hi cvanc,
I have build new amps for my set in 2007 with great succes…I also did this for my Acoustats a year earlier…

these amps are still in use on a daily basis.

just make sure you order seperate transformers for each voltage to prevent isolation issues, and it is cheaper too.

Best regards,
 

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L

lbenveniste

Member
Joined 2021
cvanc said:
Noooooooo!

Don't give up yet. Honest, get 'em fixed. They will change your audio life.

I was laying it on thick 'cuz this amp is just an awful first project for someone. But... so what? "Who does the work" isn't really the next topic here - it's "what work needs to be done"?

Here's what I suggest: Start that thread! Much can be learned from thorough visual inspection so post a ton of nice clear photos. I'll chime in. Mine have blown up so many times I'm a bit of an expert. Unfortunately ":^)

Also, find someone with a tube tester that can test 36KD6. Be careful removing them as they sometimes break at the base.

Ask all the questions you need about getting the amps off the cabinets and opened up. There's a couple other 2 series users here and it is a freakin small club world wide.

(Post a thread here asking for local help, maybe?)
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Okay, okay, Ill keep going. Pics soon. :)
 
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esl 63

Member
Joined 2010
stokessd said:
I'd love to see pictures, as I've only ever seen the panels in the flesh. I have seen pictures which looks like the lenses are made of cardboard, that can't be right...

Shel
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Looks and feels like cardboard... however they are curved and braced, and there is almost zero pressure difference between back side and front side, so not much force is applied and by that, no vibrations in the material. I braced the box quite much with wooden ribbons on the inside, gaining a lot of stiffnes and very little extra mass and negliable volume decrease.
 
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amail

Member
Joined 2023
kcin said:
Congratulations on the Beveridges

Still amazing speakers after all these years. I have Model IIIs that I have modified to run with pure tube direct drive amps

While the electrostatic elements are fragile with careful handling they will slide out and should be vacuumed. I know that Rick Beveridge used compressed air - I would be careful to avoid that. You likely have lots of remnants from the foam grilles in the stators.

The aluminized film should not be peeling and you should not be able to see straight through it. Otherwise it cannot be tensioned with heat if it is sagging. It should be ok.

The stator elements will be very brittle.. be careful . there may be some missing. This was likely done at the factory as they were pulled from molds or if there were hot spots

The amps will have to be completely serviced with new sockets and new components. The transformer is a weak link but hopefully you are lucky.

Nice find,
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Do not!! follow instructions for sliding the panel out as in Model 3. The 2SW panels are screwed in place to a wooden frame from the rear of the cabinet.

Start with the amplifier, if already not done so (the 12" woofers are your last worry). Most problems occur with the power trafo - it dries out over the years. Check it still works - if not, there are alternatives. Second - the tubes. They are old, but there are alternatives. Get the amp to work properly first (there could be other amp components that failed). You can then place speakers on top and try them out. If they play at equal level, you're in luck. If not, swap the speakers on the amps and check if the lower level sound moves with the swap. If it does, the speaker is the culprit. If it doesn't, the amp is the culprit which means more amp troubleshooting. Apply EQUAL repairs to both amps, whether required in both or not.

Warning!! - working on the amp implies that you know what you are doing. Fatal voltage inside - +/-3200V. So be careful.

The back of the speaker can be taken off. Inspect the 3 transducers, the aluminzed membrane (use a flashlight) through the tines of the stators). Hopefully, they are stretched and nice.

Model 2SW1:
30-20KHz +/- 3db
ESL: 100Hz and upward (ie. crossover 100Hz)
Woofer: Downfiring 12", sealed enclosure.

All this is for starters. Good luck.
 
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cvanc

Member
Joined 2015
I've lived with these amps long enough to do really hard searches for both transformers and tubes.

For transformers - I've never seen an original one for sale. Aftermarket replacements do not exist but I know they used to as one of my amps has one. The only available repair is to retrofit multiple off the shelf transformers.

For tubes, nothing else works other than 36/40KD6. Not as a drop in replacement anyway. So no, alternatives do not exist. I wish they did!
 
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amail

Member
Joined 2023
I personally know people who had luck with both. For tubes there are several options, one may be:

https://www.tubesandmore.com/products/vacuum-tube-36kd6-40kd6-beam-power-amplifier

Just check that pinout match, I think one of the guys (model 2 owner) had to replace the socket, if I recall correctly.

As for trafos, I know an electronic engineer in Chicago who did several new ones, custom-made, for Rick Beveridge (son of). There are a few caps worth replacing too, but that's trivial. However, if your amps do work - leave them alone FTTB (if it ain't dead....).

Another guy switched to stepup trafos + dividing network and uses his own amp, but that's another story - I guess that's not your approach.
 
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