Simplistic MosFET HV Shunt Regs

I resolved my transistor sourcing problem by ordering the transistor set from Mr. Tea Bag's group buys. Wouldn't it be cool to figure out a good alternative part? 2SK117 isn't coming back, as far as we know.


Well, here's a different thought: I'm wondering if anyone has tried the "bias multiplier" idea described by Walt Jung, in the CCS of Salas' regulator. see:
www.waltjung.org/PDFs/Sources_101_Letter_Revisit_0409.pdf

He claims a 10 dB noise improvement. It might only be worthwhile if you're using it for a MC phono preamp. Looks hard to fit it onto the PCB, flying parts off the board and all. anyone tried?
 
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I resolved my transistor sourcing problem by ordering the transistor set from Mr. Tea Bag's group buys. Wouldn't it be cool to figure out a good alternative part? 2SK117 isn't coming back, as far as we know.


Well, here's a different thought: I'm wondering if anyone has tried the "bias multiplier" idea described by Walt Jung, in the CCS of Salas' regulator. see:
www.waltjung.org/PDFs/Sources_101_Letter_Revisit_0409.pdf

He claims a 10 dB noise improvement. It might only be worthwhile if you're using it for a MC phono preamp. Looks hard to fit it onto the PCB, flying parts off the board and all. anyone tried?

-2SK880GR on SMT to Through Hole adapter.

-Don't know anyone who tried or how influential this heater lifter reminding VDS boost addition in the reg's CCS might end up for a tube phono preamp, given the usually not so good 1/F noise region in most (where that cascode CCS mod benefit coincides), but its worth making an experiment I guess. Watch the power dissipation on the non sinked lower floor MOSFET when boosting its VDS multiplier ratio. Better not dissipate more than 0.75W long term in conjunction with your master current setting.
 
Is SSG = ccr in Russian? If yes I have some SSG-2 ones and they are definitely magnetic.
Yes, SSG=ССГ. I read you message too late, can't prove exactly SSG, but tested several other. (Sorry for off-topic - feel free to delete the message)
Non-magnetic: FT-3, МБМ, К73-17.
Magnetic: К40У-9, К42У-2, К75-10.

I should mention that it is just a fun for me. Never take care about magnetic or not.
 

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Both the Audiophiler caps and the Solen FCs re pretty average 'sound wise' at signal level, but maybe perfect for the Reg.

I finally selected a Solen cap as the decoupling cap for the MSB pins of the NOS dac over about 60 others, so unusual situations can easily surprise you, and not a whole lot of $s to try them out - I think they're still 'Solen' but who knows ...

Glassware Audio offer the Audiophilers as an 'initial starter cap' in their Aikido kits and not a 'total disaster' with the substantial voltage across them

The other 2 Kemet caps are unknown altho a bit familiar - the C4A is listed as a 'Snubber Cap' so could be worth a look - the R47 category is unknown for the last cap (safety cap??) and little stock at Mouser anyway.

Sorry I can't be of more use ...
 
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-2SK880GR on SMT to Through Hole adapter.

-Don't know anyone who tried or how influential this heater lifter reminding VDS boost addition in the reg's CCS might end up for a tube phono preamp, given the usually not so good 1/F noise region in most (where that cascode CCS mod benefit coincides), but its worth making an experiment I guess. Watch the power dissipation on the non sinked lower floor MOSFET when boosting its VDS multiplier ratio. Better not dissipate more than 0.75W long term in conjunction with your master current setting.

Could I try using attached pic?
 

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Felipe, all I know is what you know by watching the Jung schematic. Just copy exactly. This is HV environment we got here also. Be careful, not sure what it can bring. One thing I can see is that the previous current set will probably go up, so check that right away.
 
Merlin, it took me pretty long to see what was the difference between those schematics! more coffee.
in fact they're not different, except one of them has all the current going through the adjustment trimmer. I'm not all that expert, but I expect it's fine as long as that trimmer is rated to handle it. With maybe a 3x safety margin?
You've also omitted the zener which is meant to protect against G-S breakdown. Jung's schematics don't show them. The device is cheap, I suppose. I'd probably put the 1 Meg in parallel with the 12v zener.
 
that is right.
again, I can't say I'm an expert on the subject, but I think the voltage across the trimmer and the 10R test point is equal to the Vgs of Q2. actually I'm sure of that part. What I'm not sure of is if that Vgs would be different with this "bias multiplier" arrangement. I thought not...but I'm not certain. Without R3, I'd want to use a 1W trimmer.
Another thing to consider is that the minimum voltage across the whole CSS is a little higher, right? The "multiplying" going on is for Vds of Q2.