I think I found out the problem of the first v4 schematics in red mode.Matlevo12 wrote: ↑02 Apr 2021, 14:41Wow, that's cool, which schem did you base your mods on ?
I compared the two V4, but my v4 is REALLY noisy (like synth fuzz noisy) when I turn the knobs up in the red mode so...
The V4 rev 1.5 is dead silent on comparison, probably because off all the independent bias voltages, and probably with that negative feedback to ground.
I measured them, just in case that interests someone :
Power supply
8.86V
UC1
3 4.07
5 4.12
UC2
3 4.13
5 4.12
UC3
3 4.43
5 4.44
I'm going to try the two mods on my v4 rev 1 :
- negative feedback of the first opamp to ground instead of Vb
- 100nf cap between Vb and gnd close to the second opamp
EDIT : Just tested the two mods. The fuzz drone is STILL HERE. STILL. If anyone has an idea before I DETROY THIS CURSED PEDAL, I'm all ears
I modified my build of V4 clone, I made the additional opamp have higher gain, and the problem happens.
it is like a drone noise, same with the synth players.
This is what I noticed, there is no resistor between the output of the opamp and the clipping diodes(LED). I put 1k resistor then the problem disappears.
Maybe that is the reason why in the V4's version 1.5, there is a 10k resistor between the opamp's output and the LEDs.