This is in regards to the Median Compressor. I initially had a similar problem as @ninjagrips as described in this thread. I initially built my Median with some TO-92 2n5457s I had in my stash. But like ninjagrips, I could not get the S-G voltage anywhere near 1.875V. However, in this state, the pedal did pass a signal when engaged. But since the voltage was so far off, I removed the through-hole JFETS with some known-legit SMT MMBF5457s I got from Digi-Key.
However, in removing the through-hole Q2, I slightly lifted the Drain trace. It was pretty subtle, and I assumed/hoped it wouldn't matter with the SMD replacement. But once I got it all soldered up, I got no sound when the pedal was engaged.
So I touched up my soldering, and additionally, I used a bit of spare lead to make a new trace from Q2's through-hole Drain pin to the Drain pin on the MMBF5457.
Now the pedal appears to work. It passes signal when engaged, and adjusting the knobs has an effect. My question is, how do I know it's working correctly? I don't have a lot of experience with compressors, so I'm not sure if I should consider this as good or still broken. With the compression and mix knobs maxed, it's still pretty subtle.
I guess a more specific question is: what should the voltages for Q2 look like? That might give me a hint if my PCB "surgery" is good or not.
Any other items I can check to verify Q2 is good?
Thanks!
However, in removing the through-hole Q2, I slightly lifted the Drain trace. It was pretty subtle, and I assumed/hoped it wouldn't matter with the SMD replacement. But once I got it all soldered up, I got no sound when the pedal was engaged.
So I touched up my soldering, and additionally, I used a bit of spare lead to make a new trace from Q2's through-hole Drain pin to the Drain pin on the MMBF5457.
Now the pedal appears to work. It passes signal when engaged, and adjusting the knobs has an effect. My question is, how do I know it's working correctly? I don't have a lot of experience with compressors, so I'm not sure if I should consider this as good or still broken. With the compression and mix knobs maxed, it's still pretty subtle.
I guess a more specific question is: what should the voltages for Q2 look like? That might give me a hint if my PCB "surgery" is good or not.
Any other items I can check to verify Q2 is good?
Thanks!
