Strange MIDI Issue JVM410C

RobK · 06-03-2009, 08:56 AM

OK, I've been pulling my hair out with this one…

I simply want to change my amp channels from a Line6 XTLive (running in front of the amp) and it WORKS as advertised...

My problem is that there is a steady, god-awful noise accompanied by a high-pitched whine coming thru the amp on the high-gain channels (it's there on the clean channels as well but not as pronounced). If I unplug the MIDI cable OR the 1/4 to the amp it breaks whatever loop is going on and the noise stops.

It seems like maybe a grounding problem but I'm not sure what to do with it.

I can turn the XTLive off AND disconnect the power chord and the noise continues so it's something looping through the metal chassis of the floorboard as opposed to generated by it.

Also just FYI, I'm not running any amp or cabinet models in the XTLive, I'm just using it as a glorified stomp box for comp, EQ, delay etc. but like I said, I can turn it off and disconnect the power chord and the noise persists as long as the MIDI and amp inputs are connected.

RobK · 06-11-2009, 02:14 PM

Problem solved. Desolder (or in my case "break off") pin 2 on one or both ends of your MIDI cable. It's not used by the amp but it breaks the ground loop problem between the amp and the Line6 XTLive.

Works perfectly. I'm a happy camper (doing alot less tap dancing).

- Rob

06-03-2009, 08:56 AM	#1 (permalink)
RobK Junior Member Join Date: Jun 2009 Posts: 2	Strange MIDI Issue JVM410C OK, I've been pulling my hair out with this one… I simply want to change my amp channels from a Line6 XTLive (running in front of the amp) and it WORKS as advertised... My problem is that there is a steady, god-awful noise accompanied by a high-pitched whine coming thru the amp on the high-gain channels (it's there on the clean channels as well but not as pronounced). If I unplug the MIDI cable OR the 1/4 to the amp it breaks whatever loop is going on and the noise stops. It seems like maybe a grounding problem but I'm not sure what to do with it. I can turn the XTLive off AND disconnect the power chord and the noise continues so it's something looping through the metal chassis of the floorboard as opposed to generated by it. Also just FYI, I'm not running any amp or cabinet models in the XTLive, I'm just using it as a glorified stomp box for comp, EQ, delay etc. but like I said, I can turn it off and disconnect the power chord and the noise persists as long as the MIDI and amp inputs are connected.

06-11-2009, 02:14 PM	#2 (permalink)
RobK Junior Member Join Date: Jun 2009 Posts: 2	Re: Strange MIDI Issue JVM410C Problem solved. Desolder (or in my case "break off") pin 2 on one or both ends of your MIDI cable. It's not used by the amp but it breaks the ground loop problem between the amp and the Line6 XTLive. Works perfectly. I'm a happy camper (doing alot less tap dancing). - Rob Last edited by RobK; 06-11-2009 at 10:31 PM.

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