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i'm on a roll... the kgsshv


kevin gilmore

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Are there discernible advantages over the fqp supply? It seems like you'd only want to use the sic supply only if you're going to bump the current above the default(?) 14ma.

 

I'm not expecting any profound difference, it's mostly that we can do away with the current limiting and that the amp will be mostly SiC fet.  Including the rectifiers...  :) 

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I recently noticed a strange behaviour of my good old KGSSHV which has probably been there from the beginning, but has gone unnoticed with the 009. Now I have the 007 and I had to turn up the volume a few clicks (elma stepper). I now also notice it with the 009, because I now what to listen for. During the warmup phase, one channel presents a sizzling noise which is clearly noticeable but not loud. After the amp has been running for some time, it dissappears. 

 

Does anyone have an idea?

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I have removed the amp board and visually checked it. Also used the opportunity to add 100ohm input resistors. 

The problem still persists. The sizzling changes in volume when I turn the volume pot. 

If the sizzling originated from some arcing, changing the volume should not have and impact? yes?

There is no audible physical noise coming from the amp.

Edited by insanity
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The first thing I did was checking balance and offset. Both were good. I will try my best to describe what I hear. Its a noise similar to what you hear, when you push the headphone cups against the head but less loud/less pronounced. It is not continous, more like there one second, gone the other. The volume of the sound becomes louder when I turn the stepper to increase the volume. 

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So I take it that it is not a noise you hear from the amp itself, but only from the headphones. Does touching your case at all affect the sound or its intensity? What is your grounding scheme for your XLRs and pot as well as your amp/psu boards ?

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Yes I hear it only through the headphones. Touching the case has no effect. My XLR input jacks are both directly connected to the chassis. Chassis is connected to earth. 

 

The amp boards are connected to ground through the psu board. 

 

I just turned on the amp again and this time the problem did not appear (the amp was off for 1h). hmmm. I guess I will watch it and report back. 

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

 

!!!

 

no ground plane on that one, everything floats 8)

 

It fits in the 5U pesante amplifier chassis with room to spare.

 

3 x power transformers mounted to the back panel

 

hv power supply mounts vertically, one on each side

 

kgsshv power supply mounts vertically on the bottom

(not a lot of heat because less current draw for the gain stages)

 

either gain stage board, 1 each side mounting vertically

and output stage board, 1 each side mounting vertically

 

of possibly gain and output stage on the same board.

(going to be close)

Edited by kevin gilmore
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Fascinating. For those of us a little late to this party, what is the purpose of this..? I found on this thread from 2010, which makes it sound like the purpose of the Cyclotron is to make a fully-complementary, fully-symmetrical electrostatic amplifier. Is that right?

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