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Annoying Finding About Acoustic Guitar Amps


capmaster

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While dealing with the ground loop problem of a forumite, I researched a bit on acoustic guitar amplifiers. The disappointing result was that most of them do not come with a ground lift switch for the entire unit. [thumbdn]

 

When playing a hybrid guitar through two amps, one each for magnetic and piezo signal, one of them must allow for lifting ground. Otherwise there will appear hum. There are two ways out, either a 1:1 signal transformer for one of the signals, or use of two wireless systems. A stereo wireless system would cause the same trouble on the receiver's side.

 

Double-insulated power supplies allowing for lifting ground are standard equipment in consumer electronics and shouldn't cost that much. Why do only very few manufacturers of acoustic guitar amps use them and add ground lift switches?

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Is this an issue with European power? I don't think we have those issues in the US.

The problem which made me research occurs in California:

 

http://forum.gibson.com/index.php?/topic/116900-yet-another-lifeson-axcess-question/

 

Ground loop problems exist in any AC line power system as soon as two or more units are grounded and connected otherwise the same time, in particular with unbalanced signal lines.

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In California they have to deal with shifting ground too.

It is a problem, depending on the distance from the epicentre and its value on the Richter Scale.

Considering magnitudes and frequencies, these ground shifts are beyond all sorts of electrical troubleshooting. [crying]

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