ESL Amplifier

[bjackson]

Has anyone considered DIYing an amplifier with multiple output devices and low current capability that should be able to drive an ESL panel without use of transformers?

 

[Williams Audio]

built in amp for ESL

hi.
if i understood well you meen a built in amp for ESL.
Acoustat made that years ago, idon't remember the model,
it was a tube amp. that worked at around 6KV and with out
audio trafo, idon't know how good it was. if you find some thing
please let me know.
regards williams

 

[SY]

Schematics for the old Acoustat amp are floating around the Web. It used a stacked pair of HV triodes and was not terribly reliable.

 

[bear]

There were also two designs in Audio Amateur for tube based direct drive ESL amps.

I think the original post was about a solid state amp to drive ESLs... the problem with solid state parts is that they still do not do well with kV floating around...

I think the problems with the Acoustat amp revolved around heat and stability... both problems presumably could be overcome. I think it used "sweep tubes" in the output, but I haven't looked at it in some time...

Seems to me that you could make a decent ESL amp with some 4-65s or 4-125s or even 3-500s or 4-400s (larger than the aforementioned tubes) or similar transmitting tubes.

But it's probably easier and simpler to just do the xfmr step up routine in the end.

Beveridge made a direct drive amp as well... never saw one of them.

_-_-bear

PS. a simple trick that has been published is to use the primary side of a tube amp (like a ST-70 or MkIII) with a light load on the secondary side (ie. 16-32 ohms) coupled from the primary with caps... gets you fairly large HV swing. Not as much as with a transformer in most cases, but surely enough to make 'em play.

 

[guglielmope]

Hello,
do you have never visited this site:
http://www.shackman.de/
there is an interesting project that I'm building, about a tube amp from 300Hz directly coupled with one electrostatic pannel.
Also here you find a full range amp:
http://www.machmat.com/mysys/index.htm
Let me know what you think about.
Ciao
Guglielmo

 

[georgehifi]

bjackson here is the Shackman on ebay if your interested HT seems to be 600v, comes with ht poweramp and pannel.

http://cgi.ebay.com.au/SHACKMAN-ESL...01615391QQcategoryZ109837QQrdZ1QQcmdZViewItem

Cheers George

 

[wrl]

Just my 2 cents, a direct drive esl amp would be pretty dangerous to have around. Thats a lot of voltage traveling through the speaker wires... if anyone who wasn't experienced were hooking them up there could be some serious risk.

I guess its not as much of an issue if you don't have kids or munching puppies or anything, but its much easier to isolate the high voltage with the use of a step-up transformer.

-Wes