Genz Benz GBE 600 noisy crackling highs

mambo4 · #1 08-25-2010, 01:52 PM

My trusty GBE started wussing out on the high mids and highs lately. It's noisy and crackling,and quiet.

I have yet to confirm it's just the amp via a second speaker cab, but Im suspecting its the amp.

I confirmed that it's the power amp section - the DI sounds fine.
I can EQ the power amp section , killing the highs and get rid of the noise/crackle, So I can still gig with it, but the stage sound is a kinda annoying.

Usually any noise issues are cleared up by hitting every input jack with contact cleaner, but I've gone through every jack and cleaned it several times over, no improvement.

If I confirm it's not my cab, is this gonna have to ship bakc to Genz-Benz?

johnk_10 · #2 08-25-2010, 02:32 PM

it sounds like it's your cab to me.

davidb · #3 08-25-2010, 03:50 PM

Funny you should post this. I usually use in-ear monitors but on the job before last at St Pete Times Forum I went old school, cranked pretty loud, I also got the kind of noise you describe.
Last job I just did I went back to in-ears, clean, no noise through my GB-600.
Problem=cabinet.
Good luck.

agedhorse · #4 08-25-2010, 04:15 PM

Try bypassing the effects loops on your amp with a short shielded instrument cable, it's possible that either there is some debris in the internal return jack normalling switch or, as I just recently saw on another model, a cable had been used in the effects loop that was not a quality cable and had bent the inside of the jack (and left a piece of itself too) damaging the switch.

Another possibility is a bad tube. The GBE-600 was first introduced in 2001 so yours could be as old as 9 years an it's possible that the tube is failing. This would only happen when using the tube channel of course.

If it's something else, no worries as we still service the amp and have parts in stock.

mambo4 · #5 08-28-2010, 05:58 PM

Confirmed that it's not the cab.
Definately the head.
the problem happens with either pre amp channel (or mixed)
Even when I use the POST DI (The DI used PRE works without trouble.)

looks like I need a repair shop.

Sadly, I'm in Seattle, which is not listed as having an authorized service center nearby...looks like Portland is the closest. Am I gonna have to ship this thing?

agedhorse · #6 08-28-2010, 07:20 PM

PM me and I'll look into this for you. Did you bypass the effects loop?