AMI 'Spirit of 76' (Median Compressor)

[ninjagrips]

Okay, when measuring between pins 2 and 3 I get 0 Vdc to -.6 Vdc on Q1, at either end of the trim pot.

 

[andrewsrea]

Where did you get your 2N5457 FETs?

 

[ninjagrips]

Pretty sure it was Stompbox Parts, but it might have been Tayda.

 

[andrewsrea]

Pretty sure it was Stompbox Parts, but it might have been Tayda.

Check for proper FET orientation, if you have not already.

Then and if you have a signal generator, throw a 1kHz sinewave into the pedal and adjust by sight and sound. You will be looking for a linear (smooth, not jumpy) reduction in volume as the 'Compression' control is turned to the right. have the 'attack' and 'release' on fast (counterclockwise). If it really jumps in drops or visually begins to truncate a side of the sine wave, your FETs may be too out of tolerance for the trim to correct.

 

[ninjagrips]

Got some new 5457’s, and I was finally able to get the voltage correct.

Thanks for your help, it sounds much better, now!