first act delay woes

[Rodgre]

I did a couple of mods to the infamous First Act delay pedal but now have the strange issue of the pedal's sound dying out after about 20 seconds. Once I unplug the DC connection then plug it back in, it's fine for another 20 seconds and then fizzes out.

What might cause this?

Roger

[PRR]

What did you "mod"?

The symptom suggests you failed to connect a bias resistor, so the circuit goes out-of-bias after a few seconds. Like a vacuum tube missing its grid resistor.