Ground Hum Testing

[tonefreak]

I did a search but could not find a thread that covers this in one place.

In testing pedals, I was wondering some of the proper methods you all perform in testing for hum generated from a bad ground connection.  For example, is having your amp and pedal connected to a power conditioner and PedalPower a good prerequisite?  Shutting off overhead flouresent lights?  Using a single coil guitar as the test piece?

I test in the most horrible conditions and would like to set up the optimum conditions for testing ground hum issues.

Thanks!

[Pushtone]

Good question, this is what I do.


Test a new build for ground hum:
Always test one pedal at a time.
Test first with a battery, then an external PSU.
Always plug the amp and pedal adapters in the same circuit.

Testing your whole rig for ground hum:
Plug straight into your amp and gauge the hum.
Swap cables to make sure this is the minimum amount of hum.
Double check you don't have any speaker cables in the mix.
This is as good as it will get without modifying your guitar.
Connect one pedal at a time using only batteries.
Add in the Pedal Power or adapters and start over, one pedal at a time.
If there is hum, Eliminate one pedal at a time until hum is gone.

Some hum's I've been able to fix, others not.
Some of my pedals hum with one amp, but not another.

I too would like to be able to make it less hit and miss.

http://www.geofex.com/fxdebug/fxhum.htm

[tonefreak]

Do you check to see the effect of having the pedal engaged vs. not engaged?

I have also found that the "normal" single coil hum is different with different amps, which could be frustrating at times.

I like what you have suggested above and will implement some of that with my following routine:

1) Amp and pedal power source (wallwart by Fulltone) connected to the same electric source.
2) Pedal Off - make measure of the hum... with single coils, it's alway there, but I make note of how much.  Make note of hum with the different PU positions.  In my case, I test with a SSH PU configured guitar.
3) Pedal Engaged - make measure of the hum and compare it to the pedal off.  If it's an OD or Distortion pedal, make note of where the gain settings are as it relates to the quantity of hum.  Also go through the different PU configurations.
4) Compare the hum with your new build to another pedal of like build that you know has passed QC.  OD to passed QC OD is a good comparison, but chorus to OD doesn't say much IMO.
5) What's going on around you?  I make sure all the flourescent lights or any TVs are turned off.  Flouresents in particular reek havoc on my single coils.

In making things more optimum, I'm going to start using a Furman Power Conditioner and a PedalPower II.  I suspect the wallwart, even though its a Fulltone, could be adding some extra hum to the mix.