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i'm on a roll... the kgsshv


kevin gilmore

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ah well-played. 52mA looks good to me as well, but it's tracking this value back to RMS current before the diode that might be tricky to nail down exactly.

And the problem is that the current waveform before the diodes is nothing like a sine wave. So the RMS value which is what

all transformer manufacturers want you to specify does not exist. Why these companies cannot understand full wave diode

bridge into capacitor of specific value, and that into a resistive load of specific value i don't know. And even if you tell them

the number of turns on the primary, and wire size, and the number of turns on the secondary and wire size, they insist

on arguing with you.

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"And even if you tell them

the number of turns on the primary, and wire size, and the number of turns on the secondary and wire size, they insist

on arguing with you. "

That's because they're the ""experts""....

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  • 3 weeks later...
  • 2 weeks later...

Ididnt answer earlier because I really don't know.

KG or maybe Kerry would know.

The version 4 PSU was only on paper, never built as far as I know.

I really don't think that the 250K resistor would be needed on the version 8 psu.

As for modifying the version 8 PSU, here again you may want to PM KG to discuss this.

FWIW, my version two PSU on the version 3 PCB is working just fine. It doesnt get much simpler than this.

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i'm running way behind for various reasons.

To do the simple zener version, make the zener string a total of 450 volts. (3 x 150v zeners)

Do not populate the following (this is for the top supply, the bottom supply is the same)

Q5,Q6,Q3,Q4,Q7, lt1021

R10,R4,R7,R6,R5,R29

C16

make R25 10k to 100k. (need to test this for lowest noise)

put a jumper wire between the emitter and collector of the empty Q7

Which you can also do between the 2 ends of the missing 240k resistors

like this

http://gilmore.chem.northwestern.edu/pszeneronly.jpg

next board run i'll add a 2 pin jumper.

Edited by kevin gilmore
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  • 4 weeks later...

The power supply is working now. I used the BUZ80 instead of the Ixys 10M90S with some modifications:

buz80_26pks.gif

But the amp makes problems. The problem seems to be also the Ixys parts. I measured ~9V across R12/R19 only at one transistor. I guess this is ok? The other 3 seems to be defective (~0V across the R12/R19). I guess nearly all the Ixys parts from Littlediode were defective. Or they are fake parts. I will complain about the parts.

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All the 2SA1486's I tested were good, with a VBR in the 700 range.

The 2SA970BL's however have numbers that jump all over. The may test initially at 40-60, then go up to 170-190 for a fraction of a second and then go to 1. Not sure why.

EDIT: my bad, if I go to 1000V they (2SA970BL) test fine at 200-210. I guess testing them at 200V is not enough....

I got both from bdent. Everything I have tested from them has been good so far.

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bdent seems to have their shit together. Here's a comparison of the C3675 from bdent to utsource:

top bdent, bottom utsource:xi29B.jpg

VT69t.jpg

W6037.jpg

You can see that the utsource devices are not as cleanly made as the bdent devices. In particular, bdent devices have a circle on the front when utsource device is a dot, and the edges of the bdent devices are much redder than the utsource devices. Both have voltage breakdown around 1110V. If these are fakes these are quite advanced fakes. If someone would like to test them under a curve tracer I'd gladly drop a few in the mail to you for free. album here.

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Yes. High voltage can be lethal.

But you already know that. Right?

Please be careful.

That's what people keep telling me... :) I will definitely be taking the appropriate precautions.

Edit: NVM, why do have three PSs, are you building for other people?

Yea, I'm building three amps.

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bdent seems to have their shit together. Here's a comparison of the C3675 from bdent to utsource:

top bdent, bottom utsource:

You can see that the utsource devices are not as cleanly made as the bdent devices. In particular, bdent devices have a circle on the front when utsource device is a dot, and the edges of the bdent devices are much redder than the utsource devices. Both have voltage breakdown around 1110V. If these are fakes these are quite advanced fakes. If someone would like to test them under a curve tracer I'd gladly drop a few in the mail to you for free. album here.

The bottom ones look like every C3675 I've ever use so they are real.

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Nice work on the PS's Horio!

I llike to duck under the table with a voltage meter tied to the outputs when I first turn a new build on smile.png

EDIT: Just looking at the photos again, I can't tell if you have insulators mounted behind the output fets.

Edited by Kerry
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