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Discussion Starter · #1 ·
I had an opportunity this weekend to run my Boss GT-8 in a stereo configuration by using my Boss Cube 15 and 30 as the right and left speakers respectively. The sound was unreal! Lush stereo chorus, panning delays, separate amp simulations panned right and left, etc...

One problem though. The Cube 15 experienced some distracting hum when hooked up as part of the stereo setup. When used in mono mode no hum. When used to accept either the left or right output from the GT-8 there was hum. I changed cords. The Cube 30 had minimal hum regardless of which output it was accepting.

I was able to minimize the hum by turning up the GT-8 output and turning the amp's volume down, but there was still noticable hum during quieter playing. Anyone having a similar problem? Any insights?
 

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Discussion Starter · #3 ·
Thanks for the reply, but there is no ground switch. It has a three pronged plug, which I tried plugging into different receptacles without any luck.
 

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Try using a custom cable like this, should eliminate the groundloop. It's a method suggested by SKRYDSTRUP (they make pro rack switchers and controllers). They don't say that their switcher has anything special that makes this work on their unit but not on anything else, so it's worth a try.
 

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I have been having the same problem with my GT-8, using two vintage fender amps, run in stereo from the left/ right outputs. Run in mono, the hum is acceptable, but the moment I plug in the second amp the hum is a deal breaker. I've had the pedal for over a year and don't remember this being a problem before so I assumed it's in the pedal. I've spent hours trying different amps, cords, outlets, grounds lifts, hum eliminators, and even took the pedal to a tech who tested the grounds in the pedal and couldn't find anything wrong. Any help on a solution would be greatly appreciated. Thanks! (I haven't tried this cord config yet but may have to get the soldering iron out)
 

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Try either removing the earth connection from a jack lead and using that in the noisy amp - like Keith's diagram above but without the earth, just the top wire in the diagram.
Or try putting an isolating transformer/di box between the gt-8 and noisy amp.
Jim
 

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Take an ordinary guitar lead, cut or preferably de-solder the connection to the ground on one side.
Like this....
The trouble is at the moment you have two ground connections to the two amps, this will eliminate one but you won't be able to use the cable normally unless you re-make the ground connection!
Jim
 

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OK, so a standard guitar cable with just the tips connected made no difference. Still has the big hum. ( I'm guessing that the TRS end in the picture is unnecessary?) On the up side, I fixed a nice but non-working guitar cord. I'll try the DI next.
 
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