H9 yields bad hum when plugged in effects loop

[jackbrighton]

I love the sound of my new H9, and everything's fine when connected in-line between guitar and amp. However, when I plug it into the effects loop of my L.R. Baggs Venue D.I. pedal, there's a bad 60 cycle hum. I checked all the cables and they're fine. There's no weird RF stuff going on, and the amp itself is grounded. Seems like this shouldn't be happening! Any ideas about why?

[AAgnello]

Sounds like a ground loop. If the amp's power cord is plugged into a socket that has a ground connection and the H9's power cord (or any other gear for that matter) is plugged in somewhere else, there could be a ground differential. One possibility is that the effects loop is grounding the H9 at the signal ground and that ground is different than the power ground. Have you tried plugging the H9's power into the same place that the amp's power is connected?

[jackbrighton]

I agree it sounds like a ground loop issue, but the H9 and the amp are both plugged into the same power source.

[AAgnello]

hmm. It seems like you'll have to do some experimenting and use the process of elimination. It's really unlikely that it's the H9 but you can eliminate that possibility if you have another piece of gear that you can use in the effects loop instead of the H9. Can you try a different power supply or try the power in some other place? Does the amp have a 'ground lift'? Here's a link that might shed some light on the problem. http://www.guitarworld.com/how-eliminate-guitar-buzz?page=0,1

[jackbrighton]

Thanks for the quick replies! I'll check the effects loop with some other gear, etc., and report back when I can. LOVE the sound of the H9, so this is going to get resolved.

Cheers,

Jack

[jackbrighton]

Well shoot: the hum in the effects loop happens with my H9, but not with other effects devices. Could it be a hardware defect in the power supply or the H9 itself?

[jackbrighton]

Resolved: It turns out to be the H9 power supply is the source of the hum. I found a spare 9v/500milliamp power supply, tried it with everything connected the same and there's zero hum, just H9 beauty. Just reporting back in case this happens to someone else. 

Cheers,

Jack

[AAgnello]

Sorry that you had a problem but happy to know that it's resolved. Please send an email to support@eventide.com so that we can arrange to get the defective supply back for analysis and so that we can send you a replacement.

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