finally an electrostatic transportable

[Omega_ELS]

On 11/16/2025 at 3:30 PM, kevin gilmore said:

 

 

 

 

Hi Kevin.
Thanks for your reply.
The boards are sandwiched together with a thermally conductive material and a bunch of thermal paste between the housings.
I couldn't figure out an easy way to get inside without breaking everything.

 

I'm hoping the problem is still in the power supply, since you're right—it was heating up.
The diodes were burning out frequently, then the transistor itself, and then possibly the transformer itself—its resistance is now 0.1 ohms on the primary winding and 4 ohms on both secondaries. I'm not sure if that's normal.

 

It's been working without any problems on a third-party power supply for half an hour now. I'll continue testing.

 

 

I couldn't think of anything simpler or better than connecting 4 of these modules to get +-400v

To my surprise, these modules produce even more than 10mA and +-400v

But they have one major drawback: noise. The throttles in them make noise.

Edited November 19 by Omega_ELS

[kevin gilmore]

links for those power modules please.

how warm does the chassis heatsink get?

edit: what is the total power input that runs the switchers? 

Edited November 16 by kevin gilmore

[Omega_ELS]

7 minutes ago, kevin gilmore said:

links for those power modules please.

how warm does the chassis heatsink get?

https://www.ebay.com/itm/275736642694

 

 

its max MAX1771 12v to 150-220v DC
it can be ajusted 
i set 200v and just connected it 200+200 for +400 and 200+200 for -400

 

I read a similar problem about noise here but I couldn't find a solution.

 

Well, unfortunately, I don't have a thermometer or pyrometer, but it feels like it's probably about 45 degrees Celsius or so - maybe more/less, It dissipates pretty well. 

 

 

Edited November 16 by Omega_ELS

[kevin gilmore]

those are not isolated. at least they sure look non isolated. how you put them in series with common power supply input. 

[Omega_ELS]

1 hour ago, kevin gilmore said:

those are not isolated. at least they sure look non isolated. how you put them in series with common power supply input. 

i use 4 of this one

https://www.lcsc.com/product-detail/C5279972.html

DEXU Electronics B1212LS-1WR3

it's something like galvanic isolation

 

 

Edited November 16 by Omega_ELS

[Omega_ELS]

1 hour ago, kevin gilmore said:

edit: what is the total power input that runs the switchers? 

It's been working reliably for an about hour now.I will continue testing 24\7.
The power consumption of the modules themselves from the 12V power supply is 550 mA under load.
The power consumption of the amplifier itself from these modules at +-400 V is only 5.5 mA.

[kevin gilmore]

the dexu parts are providing the isolation. this works. extra parts, maybe the same performance.

Edited November 16 by kevin gilmore

[Omega_ELS]

On 11/16/2025 at 6:42 PM, kevin gilmore said:

the lcsc parts are definitely isolated.  they work fine.

the maxim boards are not isolated and you cannot put them in series because input ground and output ground are tied together.

 

Yes, you're right.
That's why I had to connect it like this.

 

 

On 11/16/2025 at 6:42 PM, kevin gilmore said:

this works. extra parts, maybe the same performance.

I'll get this thing tomorrow
12v to +-390v DC DC
I hope it doesn't beep
or at least there's a way to eliminate the beeping with an RC filter or something.

I'm just trying to try all the DC-DC modules before spending $50+ on those cool USA12400S-8 ones. But most likely, I'll just have to buy them.

 

 

 

 

Edited November 19 by Omega_ELS

[kevin gilmore]

those modules do work, i have a few. the diodes on the back run stupid hot. never tested for hours and hours. there was a company in poland i think building an electrostatic amp with 4 of these. first version with no fans. second version with fans. both versions burn up in a couple of months.

[kevin gilmore]

so my version has an amplifier power of around 20 watts.  the hvrv version seems to be half of that. may be the reason why there were a couple of comments about the sound vs the original to126 version.

[Omega_ELS]

 

 

On 11/16/2025 at 7:18 PM, kevin gilmore said:

so my version has an amplifier power of around 20 watts.  the hvrv version seems to be half of that. may be the reason why there were a couple of comments about the sound vs the original to126 version.

Well, if I turn the volume up to maximum, the amplifier can consume up to 10 mA at peaks, but I don’t listen that loud. I dont know if its minited to +-400v or maybe it can handle more.

Edited November 17 by Omega_ELS

[Omega_ELS]

On 11/16/2025 at 6:44 PM, Omega_ELS said:

 

 

 

 

I'll get this thing tomorrow
12v to +-390v DC DC
I hope it doesn't beep
or at least there's a way to eliminate the beeping with an RC filter or something.

I'm just trying to try all the DC-DC modules before spending $50+ on those cool USA12400S-8 ones. But most likely, I'll just have to buy them.

 

 

So I connected this yellow DC-DC.
It can produce -400 and +380 volts from 12 volts.
Which is 20 volts less than I need.
Interestingly, it can produce -400 volts in one side.
And only +380 volts in the other. Funny.
Now I'll be looking for ways to squeeze another 20 volts out of it.
Or should I just skip the hassle and buy some decent USA S400 modules and be done with it.....

Edited November 17 by Omega_ELS

[Michelag]

14 minutes ago, Omega_ELS said:

So I connected this yellow DC-DC.
It can produce -400 and +380 volts from 12 volts.
Which is 20 volts less than I need.
Interestingly, it can produce -400 volts in one side.
And only +380 volts in the other. Funny.
Now I'll be looking for ways to squeeze another 20 volts out of it.
Or should I just skip the hassle and buy some decent USA S400 modules and be done with it.....

Perhaps Better to get down go 380 the other one, no?  

[kevin gilmore]

that is a dual voltage output, single ended flyback supply.  can't change the positive voltage without changing the negative.

so you really need 2 x single output units. and then you might be stuck with +/-380.  which should work.

[Omega_ELS]

1 hour ago, kevin gilmore said:

that is a dual voltage output, single ended flyback supply.  can't change the positive voltage without changing the negative.

so you really need 2 x single output units. and then you might be stuck with +/-380.  which should work.

Hi Kevin
Well, it still works.
It's just that the voltage distribution isn't ideal for -400V and +400V.
I'm not sure if it's possible to supply different voltages.
The sound is good and quite clear.
But I think I'll still have to buy those proper modules and settle the power supply issue—there's no way to get +-400V 6mA for under $50.

[Omega_ELS]

So, I've been testing it for two days.
It's thermally stable for 12 hours.
I think the tests can be completed.
I just don't know what the upper power limit is.
I tried +-400V and it works.
And even at +-450V.
I wonder if it can withstand +-500V or 600-700-800V?
I saw someone build it with four 400V modules.
So, +-800V.

[kevin gilmore]

assuming the parts are stn9360 and matching npn are 600v parts the front end limits to +/-600v. with cascodes you can get to +/-900.   anything over +/-600v will damage the headphones.

[psyduck]

On 10/27/2025 at 8:43 PM, spritzer said:

CRCW's should be just fine so something else might be drifting there.  

Does your board have a ground plane?

[spritzer]

I always have a ground plane or rather two, on both sides.