Trouble when biasing the JFETS on Mofeta Preamp

[trymlg]

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

 

[Einzeln]

Did you try turning the normal channel down?
4,5volt is right.

 

[trymlg]

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.

 

[anevilspar7an]

Did you confirm pinout direction on your JFETs? And make sure the solder joints aren't cold joints.

 

[Einzeln]

Does it sound anything like this?

 

[trymlg]

Did you confirm pinout direction on your JFETs? And make sure the solder joints aren't cold joints.

yes, but I've now zoomed in and there's a chip in the MMBF5457-chip on Q1. I mistook Q3 for Q4 (they're right next to each other lol), so I think I've figured out. Had to pull out the pin socket, and purchase a new JFET. thank you for the help!

 

[anevilspar7an]

Of course man, most of the time it's the little things that make us want to pull our hair out over a project.