flakeygeek2000
New member
My Rebel 30 MKI Head had to go to the shop after one of my cats hacked a hairball into it.
The amp got substantially fixed except for the effects loop. I did some experiments and
took some measurements.
Before the cat incident, the fx loop worked well with my Strymon Bigsky, sounded just glassy and wonderful. Now there is added hum.
I did some experiments:
fx send cabled to fx return = good
fx send to Strymon Bigsky in, Bigsky out to FX return (normal effect in loop configuration) = hum added with desired sound
fx send to Strymon Bigsky in, Bigsky out to humbuster to FX return = loud hum
Cable from fx send to input of Strymon Bigsky (nothing plugged into fx return) = no added noise
1/4" jack that shorts signal to ground plugged into fx return = medium level hum
1/4" jack that shorts signal to ground plugged into fx return and shorted to ground of fx send = silence
I took some measurements with a DMM:
fx send gnd is 10 ohms to board gnd
fx return gnd = can't find it tied to anything
I really don't want to take that whole board out to see if the fx return jack is broken or
somehow no longer has a ground connection. Any hints or suggestions that make sense of this
new reality would be appreciated.
Alan
The amp got substantially fixed except for the effects loop. I did some experiments and
took some measurements.
Before the cat incident, the fx loop worked well with my Strymon Bigsky, sounded just glassy and wonderful. Now there is added hum.
I did some experiments:
fx send cabled to fx return = good
fx send to Strymon Bigsky in, Bigsky out to FX return (normal effect in loop configuration) = hum added with desired sound
fx send to Strymon Bigsky in, Bigsky out to humbuster to FX return = loud hum
Cable from fx send to input of Strymon Bigsky (nothing plugged into fx return) = no added noise
1/4" jack that shorts signal to ground plugged into fx return = medium level hum
1/4" jack that shorts signal to ground plugged into fx return and shorted to ground of fx send = silence
I took some measurements with a DMM:
fx send gnd is 10 ohms to board gnd
fx return gnd = can't find it tied to anything
I really don't want to take that whole board out to see if the fx return jack is broken or
somehow no longer has a ground connection. Any hints or suggestions that make sense of this
new reality would be appreciated.
Alan