duhvoodooman
July 11th, 2009, 11:15 AM
I don't understand this behavior, so thought I'd post it here for some of you guys who have more experience with amps with FX loops:
I built a little 6-jack switch box and placed it between my distortion pedals and my time-based effects (trem, chorus, flanger, delay & reverb). The switch is then plugged into my Egnater head's input and the FX loop send & return jack. It's wired so that it will switch between running:
dist. FX --> time-based FX --> amp input --> amp FX loop send --> amp FX loop return
when off, and when switched on:
dist. FX --> amp input --> amp FX loop send --> time-based FX --> amp FX loop return
This lets me turn the switch on when running with the Egnater head and get the benefit of running the time-based effects in the FX loop after the preamp, so that they don't pick up any additional preamp distortion. When I use one of my other amps with no FX loop, I turn the switch off and just jumper the FX loop send & return jacks on the switch. The switch works great. But....
When using it turned on with the Egnater head, I noticed a pretty audible hum. At first, I though maybe I had a grounding problem in the switch, but when I removed the switch and just ran things with cable runs directly into the FX loop, it still hums. Seems to be coming from the time-based effects chain, since I can get rid of most (but not all) of the hum by turning them all off. I tried a couple of different power supplies and no change. The weird thing is that if I unplug the time-based effects from the amp's FX loop and put them back between the distortion effects output and amp input, I get NO audible hum--quiet as a church mouse.
Any of you guys have an idea what would be causing this behavior?
I built a little 6-jack switch box and placed it between my distortion pedals and my time-based effects (trem, chorus, flanger, delay & reverb). The switch is then plugged into my Egnater head's input and the FX loop send & return jack. It's wired so that it will switch between running:
dist. FX --> time-based FX --> amp input --> amp FX loop send --> amp FX loop return
when off, and when switched on:
dist. FX --> amp input --> amp FX loop send --> time-based FX --> amp FX loop return
This lets me turn the switch on when running with the Egnater head and get the benefit of running the time-based effects in the FX loop after the preamp, so that they don't pick up any additional preamp distortion. When I use one of my other amps with no FX loop, I turn the switch off and just jumper the FX loop send & return jacks on the switch. The switch works great. But....
When using it turned on with the Egnater head, I noticed a pretty audible hum. At first, I though maybe I had a grounding problem in the switch, but when I removed the switch and just ran things with cable runs directly into the FX loop, it still hums. Seems to be coming from the time-based effects chain, since I can get rid of most (but not all) of the hum by turning them all off. I tried a couple of different power supplies and no change. The weird thing is that if I unplug the time-based effects from the amp's FX loop and put them back between the distortion effects output and amp input, I get NO audible hum--quiet as a church mouse.
Any of you guys have an idea what would be causing this behavior?