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Now for something different...


spritzer
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"I don't think there ever was any Germanium sand that could handle 1500V..."

That's why you need to run about 10 devices in series.......

":) My plan is for a spud electrostatic amp with just two triodes and DHT's at that. I know ETF.12 had a competition along these lines but I'm going to be far stricter to myself. No push-pull, current sources, parallel tubes etc. Just transformer, triode and transformer... :D "

Team Overkill lives.....

An instance when less is moar..

Edited by wink
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I'm interested why you guys have decided to do a 300B electrostat amp after all. From reading old posts on Headfi I got the impression that it would be a poor idea.

I have always loved the sound from the 300Bs. With an external transformer box it didn't sound quite as clear (Border patrol pre/power with my illsions); but there is to still something about it that encapsulates me even after it was sold. Edited by Victor Chew
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I have always loved the sound from the 300Bs. With an external transformer box it didn't sound quite as clear (Border patrol pre/power with my illsions); but there is to still something about it that encapsulates me even after it was sold.

That is the reason I am testing 4x6BG4 (6C4C) in my new project for STAX. It is doable, it can play loud enough with magic of DHT's.

But work is still in progress.

post-3957-0-74688900-1358756203_thumb.jp

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The 6C4C is at least cheap so the voltage limitation is less of an issue.

What do you mean?

Choke loaded triode doesn't need  HV over 300 V, so low max Uak of 6C4C (360 V) is not limitation if you want to drive STAX. That is my opinion.

But I am not sure if I have understood you correctly (my English suffer, sorry).

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Not a whole lot of headroom with 300V.

My old T1 plays enough loud, power stage with 6C4C choke loaded plays louder. I don't need more voltage swing. I think many of us don't need as long as they have healthy hearing. Of course it is my opinion :)

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It's not really about listening at insane levels. We were well aware that an amp like the KGSSHV and T2DIY can and will burn up a Stax transducer if it were ever to see the full force of the output. Not likely to happen unless somebody were to feed it from a high gain preamp but it is something to think about. That said the amp is then just idling at normal levels so there are clear benefits to using crazy voltage levels. :)

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It's not really about listening at insane levels. We were well aware that an amp like the KGSSHV and T2DIY can and will burn up a Stax transducer if it were ever to see the full force of the output. Not likely to happen unless somebody were to feed it from a high gain preamp but it is something to think about. That said the amp is then just idling at normal levels so there are clear benefits to using crazy voltage levels. :)

True, true, I agree, but what is normal levels? I am going to make some measurements of max swing from 6C4C with chokes, when I finish prototype (testing different types of drivers).

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Why am I not surprised it is custom. :) I'm always up for some trading as well.

True, true, I agree, but what is normal levels? I am going to make some measurements of max swing from 6C4C with chokes, when I finish prototype (testing different types of drivers).

Well that's where it gets tricky as this varies quite a bit. The spec for Stax states the 100Vrms point but how they get that figure is unknown.

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  • 1 month later...
  • 2 months later...

Now here is something really different I got in the post today, a 12V-260V DC-DC switcher. 

 

zrCps3kh.jpg

 

Very small and no problem going bipolar or even stacked for super small electrostatic amps.  There is one I've already drawn up that will be rather cool..  :)

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That would work but 20W is a bit too much for that use.  :)  What about two of these stacked (+260/+520V) driving a fully balanced GES.  The tubes are run off the 12Vdc supply so the amp could be tiny, 10" by 10" and 1U tall. 

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  • 4 weeks later...

Now something to use with the mini switcher above, a subminiature tube electrostatic amp.  :)

 

tFNtDLL.jpg

 

The pcb is less than 120*90mm for both channels and it is fully balanced from input to output.  Only one B+ for both given the voltage constraints of these tubes so limited voltage swing but who cares... it will look cool.  :D

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