AMZ mini booster problem. need you help

[jamiefbolton]

Hey guys, here is the run down.

built the MB on perf. breadboarded trial run works fine. so i've messed something up.


power seems to be running ok. volt check out i think.
i used an audio probe and get sound through the Gate of the 1st JFet. no sound on the source. sound on the Drain
sound on both gate and drain of the 2nd jfet but yet again, no sound on the source.

after taking these pictures i realized that the two purple wire destinations needed to be switched. so that is now correct.

so i
m getting sound all over the place except the source, so consequently, no sound going to the output cap.

[flo]

Measure the voltages on the FETs and post them here. That will help to determine the problem.

[earthtonesaudio]

Also, you said you have sound on the Drain of the first JFET but no sound on the Source of the second JFET.  If you mean the lower/input JFET is "first," then you have a wiring error, because those two points should be directly connected.

[R.G.]

Measure the voltages on the FETs and post them here. That will help to determine the problem.

Even better than simply measuring voltages, read "Debugging: What to do when it doesn't work" and follow the instructions.

[jamiefbolton]

problem solved. mods can delete this thread. thanks for your direction guys

[flo]

Good you fixed it!
Perhaps you can post what the problem was and how you fixed it? That can help others.

[jamiefbolton]

it turned out to be a cold solder on C2/Gate Q1. and a faulty volume knob.

audio probe revealed the problem on C2. i then fixed that but to no avail, very quiet sound. kept tracing the pedal until all was left was the volume pot.

yes guys! debugging page helps! thanks to all