Echoplex Hum

[rgorke]

First, can we get an area for just Echoplex chit chat? Who makes those decisions?

Second, on one of my EP3's I get a hum when the echo on/off switch is plugged in and the echo is engaged. So, if I don't have a switch in the jack, I get echo and no hum. But, if I put in a switch, I either get no echo (echo off) and no hum or I get hum and echo.

It is the strangest thing. It is like there is a grounding issue somewhere. If I compare to my other EP3 that has no hum, everything looks the same. I also get continuity on the ground all the way through the circuit.

Any other thoughts?

[rgorke]

So, I have discovered the problem. Even though I did have continuity throughout the grounding circuit, from echo jack to sustain pot to board to record jack, the wire the connected the echo jack to the sustain pot was bad. So, even with continuity, there wasn't enough of a connection to provide adequate grounding. With a new piece of wire from the jack to the sustain pot. all is well.

I think a big lesson is that with these 30-40 year old pieces of electrical equipment, amps, pedals, delays, etc, the wires can corrode and go bad.

Thanks to the folks that helped out. Now for a new record/erase head. I ain't telling my source until we get a dedicated Echoplex or Maestro or Tape Delay section.