Hum issue with pedals

bassman515 · #1 07-25-2008, 04:30 PM

Hello, i am not sure what to do here, but i want to get some advise. I have a hum in my chain when i have the effects loop hooked up. I am not sure if any of my pedals need isolated power or not. When i have the effects loop pedals plugged into the loop, it hums, if i take it out (unplug the cables) it goes away. If i have those in and i unplug the cable going into the input of my amp, the hum goes away. Here is my chain, let me knwo what you think.

Bass-->Trace Elliot SMX EQ (Has its own power)--> BBE Optostomp-->EBS Octobass-->EHX BMS (Has own power)--> Akia Unibass-->Fulltone BAss Drive-->MXR Blowtorch-->EBS Wahone-->Ernie ball Volume JR-->Amp (There is a boss tuner going out of the tuner out of the volume pedal)
Effects out-->MXR Flanger-->Mxr chorus-->Boss DD20 gigadelay-->Effects return

I am powering these off of a DC brick. I have the tuner daisy chaining together the Wah, Delay and the Akai. Any help would be great. I thought i could get a seperat power supply to power the effects loop, but that seems silly to get one for three pedals...two of which are 18v.

Thank and i hope this makes sense.

Jeremy

RickenBoogie · #2 07-25-2008, 08:27 PM

I don't have a good answer, but I'll at least respond. Maybe add one more pedal to the chain, the Ehx Humdebugger. I use an ISP Decimator on my board, and hence have absolutely no noise issues of any kind. Wish I didn't need it for the space, but it works, and I'm happy.

bongomania · #3 07-25-2008, 08:36 PM

Process of elimination. Remove one pedal at a time to see if any one of them is the cause. If that doesn't do it, try removing two at a time. While odds are you will discover the problem that way, even if you don't it will give us more information to go on.

EADG mx · #4 07-25-2008, 09:11 PM

Try batteries, different amp, different bass. Then at least you can isolate the issue to your power supply or outlet.

astralis · #5 07-25-2008, 11:00 PM

Process of elimination is almost always the answer to get the question you're looking for. If batteries fix your loop (they often do), you may want to try different outlets around the house, or maybe in a different location. Also, make sure you're using the right variables... Find a certain pedal that you are positive isn't creating the hum, and test each cable you plan to use on your board using that pedal... and so on.

P.S. I wish I had more opportunities to post on this forum... sigh...

bassman515 · #6 07-26-2008, 07:35 AM

Will do, i need to wait to get my amp back, but then i will try things out. I have used diffrent amps and basses so i am sure it is somwhere on the board.
J

niftydog · #7 07-27-2008, 07:20 PM

Run a test with everything on batteries - if a pedal or two can't use batteries, perhaps just remove it/them from the chain for the test. If the problem goes away, you have a ground loop created by the brick and may need to consider isolated power supplies.

The most likely suspect is the fact that you have daisy chained between effects in the loop and effects out of the loop. Try powering effects in the loop with a separate supply.

A quick fix/troubleshooting aid:
Take a patch cable that you are happy to mess with, preferably one with a non-moulded jack plug. Unscrew the jack plug housing and cut/unsolder the shield connection leaving only the signal wire connected. Use that patch cable as the very first cable running to the effects in the loop. Make a difference?

You could also try that same cable in other positions in the rig to see if you can stop or lessen the effect of the ground loop(s).