Deofol OD

So that makes somewhat sense that the capacitor is for stability (and taming high frequency response purposes). Excellent progress, I’ll pull mine out and get the iron hot (watching not to score the caps :) ).
 
Got the caps across the q2 and q4 source and gate. Much better and sounds much better (didn’t try the scorching - “may it improves sound, though” :ROFLMAO:)
 
I still have to pull and measure all the caps, but here's what I can tell you so far...

The capacitor in question is directly across the Gate/Source. The original schematic was correct in that regard before folks did their "magic".

However... the Body control is completely different. Granted this version uses a toggle switch instead of a pot, and it's entirely possible that the functionality was changed at some point, but it's not the same.

There are also one or two component differences.
That is good to know. So this means the current oscillation problem is probably caused by the bad layout I guess.

Can you also measure Vpp and Igss of the jfets? I am curious if they are off the shelf component or if they are pre-selected for having specific parameters.
 
Yes, very likely. I have a much improved layout for the new schematic worked up, I'll have a prototype built in about two weeks.

I'll run the JFETs on the DCA75 as soon as I get a chance.
 
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