Wednesday, June 25, 2008

Keeping the hum down

My ultimate goal for "noise" is for my amp to sound the same whether anything is plugged into it or not. Unfortunately my amp has a hum of it's own, it's 36 years old, it's allowed to. There's nothing I can do about that, but I obsess about keeping my pedalboard silent.

I noticed I was getting more noise than usual. I tested by plugging my pedalboard into my amp and turning everything on. Once the buzz is going I pull the cable out of my amp's input to see if the hum goes away. Sure enough it did. Next I unplugged one cable at a time until the hum went away. I narrowed it down to my tube screamer but did some bypassing of cables to make sure that was the case. In the end I plugged everything back in and the hum was gone! A cable must have just been sitting wrong or something. Back to silence. Hmmmmm.

Here are some tips for keeping hum down:

Problem #1 - bad cables
It's important to have a good connection inside each cable. I openly hate George L cables (I used to use them so I can judge) or other solderless cables that reply on pressure or gravity to keep things in place. I highly, highly recommend soldering your own cables. It sounds intimidating but I promise it's worth it. I was able to buy a soldering gun, solder, top of the line cable, and connectors for less than the price of a George L kit. 15 minutes of learning to solder on youtube and I was ready. I noticed a HUGE difference in sound quality and noise reduction when I moved from a cheap hodge-podge of cable.

Problem #2 - ground loops
Ground loops are tricky thing to understand but for a guitar rig, the two things you want to avoid are 1) instrument cables running parallel to power cables (AC or DC) and 2) equipment plugged into two different power circuits. Power cables create an electronic field around them and if an instrument cable is running parallel it will pick that up and make a 60 Hz hum. Always cross power and instrument cables at 90 degree intersections. Set up your pedal board this way and also check when you're playing live that your cables from guitar to board and board to amp aren't crossing any extension cords or anything. Shielded cables will help avoid this problem as well. It's also good practice to plug your pedalboard and amp into the same outlet. I use a power conditioner in my rack and plug everything into that. I also use a Voodoo labs Pedal Power 2 for all my pedals. Both of those keep things regulated and isolate ground loops. If you're having a problem with ground loops that you just can't fix get a ground lift for your cable right before the amp.

Problem #3 - Too many buffers
I think the true bypass vs. buffered pedals is an entirely different post but I can tell you if you have too many buffered pedals in a row you'll get noise. If this is the case you'll want to mod some of them to be true bypass or get a multi-effects loop pedal like the stuff Loooper makes.

Hopefully this helps! There's nothing more embarrassing than the sound guy having to tell you your amp is too noisy. It's also bad for the sound of playing live or recorded when everyone hears your signal being unmutted at the sound board... song starts, everything's quiet, then huuuuuuuuum. Silence is golden.

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