On the subject of ground hums

[cereal]

My '69 Princeton has a small hum. If I touch a tone pot on the guitar it goes away.

If I plug a mic in or nothing at all there is no hum.

It has the 2 prong original plug. Is that my problem right there?

[JeffLearman]

Does the hum go away when you touch the strings on the guitar?

If so, then it's normal (depending on how loud the hum is). If not, then you probably need the string ground fixed on your guitar.

I remember reading a safety article somewhere saying that one should NOT have a string ground, because of shock risk. But I can't imagine playing an electric guitar, especially with single-coil pickups, without a string ground. I deal with shock risk by testing conductors I might touch (like mikes, my keyboards, etc.)

[Anderton]

 

Originally Posted by learjeff

I remember reading a safety article somewhere saying that one should NOT have a string ground, because of shock risk. But I can't imagine playing an electric guitar, especially with single-coil pickups, without a string ground.

 

Try replacing the string ground with a high-value disc or mylar capacitor (e.g., 0.22uF) rated at a couple hundred volts. That should shunt audio like hum to ground, but eliminate the direct, wired connection to ground.

[cereal]

OTOH, isn't a little hum part of good tone? :-D

If I recall, my old ADA Microcab had a feature that let you introduce hum into your signal.

[JeffLearman]

 

Originally Posted by Anderton

Try replacing the string ground with a high-value disc or mylar capacitor (e.g., 0.22uF) rated at a couple hundred volts. That should shunt audio like hum to ground, but eliminate the direct, wired connection to ground.

 

Good point! Shoulda been obvious, too. Oddly enough, the article on safety didn't mention this.

[Anderton]

Credit where credit is due...Dan Armstrong turned me on to that one.