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i'm on a roll... the kgsshv

kevin gilmore

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I went ahead and built the new PS design to make sure it's stable and performs...  :D


Here's a picture of the supply set to 400V (it's just the bottom half of the PCB). 




I've used a few different values, but that shouldn't matter.  I'm seeing about 5mV (RMS) of random noise.  Could probably get that down a bit.  Some of that is coming from my apartment.

Edited by Kerry
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kerry changed a few values from the original schematic, changing the labels on the boards now




R1 to 4.7k  (probably a good idea)

D1  12V

R6 to 50k (also probably a good idea)

C7 down to 5pf (and yes it needs to be there)


3.9 ohms for R11  if you want to raise the current limit

Edited by kevin gilmore
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powered up my kgsshv, one board is fine while the other has the outputs at +vcc. Where should I start looking?

One other thing is that the +15V on this board powers up slower than the other, will this affect the output DC?

edit: that does seem to the be problem, now it works fine but drifts around quite a bit without the servo. I started listening though so maybe I'll fix this in half a year

I haven't listened to a kgsshv in a while, the soundstage is very wide compared to other amplifiers in the lineup. can also kind of see how more bass a la carbon might be welcome

Edited by nopants
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Ordered some of the Carbon boards from Birgir.Its without cascoded CSS.
Cut those board to a smaller size.
Besides from a PZTA42 that somehow had its own way and apparantly caused a Vishay to go south the amp was up and running without too much hassle.
The Carbon definetly runs hot. The heatsink is ,45K/W - seems ok
The plan is to have the amp on one side and the PSU mounted likewise on the opposit side in a Dissipante 2U/300mm wide.
Looking forward to get the PCBs from MWL168 GB  :laugh:
Big thanks to Kevin & Spritzer.
Edited by sorenb
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@Gepardcv: you probably won't be disappointed  :laugh:

@Insanity: Depends on how you see it; a bit solder wick and some flux and off it goes ... not a big deal ...had smoke from the Vishay and had to replace that and the 42 that had its own way for some reason ...anyways its only the C2M that is going to be mounted like that ... the 10m90 will get company from a DN2540 ...just havn't figured out how to do it just yet ...

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I finished a mini-stereo KGSSHV build yesterday. It sounds pretty nice!


One problem: when I turn it off with headphones plugged in, there is a pretty loud crackle in the headphones. Not deafening loud, but disconcerting, especially since my KGST doesn't do this. There is no noise on power on. Any idea what might cause this power-down problem?

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It's a common issue with the Hv and nothing to worry about. You can put in larger PSU caps on the LV side which makes this go away.

Any idea why this power down noise doesn't happen on the ixys version of the KGSSHV onboard then? The psu is the same i assume

Sent from my yPat using Tapatalk HD

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so for original servo, adjust the amplifier for an output voltage around zero

then put the jumper in for servo v1.


for the new servo, adjust the amplifier for an output voltage around +20v

then put the jumper in for servo v2


never put both jumpers in at the same time.

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I've been putting together a BOM for the Carbon but I'm not finding any 175K resistors that are in stock over at Mouser or Digikey.  Does anyone know of other sources?  There's 174K but will that work?

Edited by chiguy
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