I was hoping someone can explain this odd situation to me.
I have 3 heads with effects loops: TSL, DSL, and an JCM 800 with a Metropoulos zero loss.
When I use my traditional pedal set up that powered with a Voodu Lab pedal power, I don't get any hum out of any of these amps. Delay and a clean boost are in the loop, a Tube screamer, Hush, and Chorus are in the front.
I then plug in a Line 6 Helix LT multi effects using 4 CM, and I get a signal hum with either of these 3 amps. I tried the ground lift on the Helix, no change, I tried the effects loop button on the rear of the heads (+4 or -10) no change. I also tried this with an old Digitech 1101 effects processor and I get the same signal hum.
Why would I get no hum using the pedal set up but get one using the Helix or Digitech and how do I fix that?
Thanks.