Trouble when biasing the JFETS on Mofeta Preamp

T

trymlg

New member
When biasing the JFETs, following Chuck D Bones' advice, Q1 and Q3's Drain wouldn't go below 18V. Black probe on GND, Red probe on D leg. chatgpt told me to resolder R4 and R8, but it did nada. Getting 0V when checking the Source leg on the JFETs.

I get decent sound through the pedal, it's just rather bass-heavy/muddy.

Also, Chatgpt keeps telling me to bias it as if the supply is 18V, because of the chargepump IC, which would have me bias them at 9V. but everyone in this forum says to set them to 4.5V. which one's right? Was gonna give this to my buddy for his birthday tomorrow. please help

IMG_1150.jpeg
 
yes, I adjusted the normal and brite-pots. I suspect the JFETs aren't conducting properly, but I wouldn't know how to get them to.
 
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