New 'buzzing' problem

[NZBassman]

About a year or so ago I posted that I was having severe 'buzzing' problems through FOH when I DI'd my bass
Anyway I since bought a Squire Vintage Modified Jazz bass (passive) and that solved the problem
Then about 6 months ago the buzzing returned (I used the DI from my Ashdown EVO 900 III)
Ashdown said the amps DI has a built in ground lift, but I was still getting buzzing... We've done all the usual - changed leads, tried different channel on the desk...etc.... to no avail
So I bought myself an external active DI (Behringer) and that worked a treat.... until 3 weeks ago when the buzzing returned yet again.
I ended up using drummers old kick drum mic on my cab and it worked fine.

I was wondering it keeping the DI box on top of my amp might be a problem? - seeing the DI has a 9v battery in the back.. or should I put the DI box on the floor or somewhere else?

I'm at my wits end here and getting very frustrated!

any advice would be helpful

 

[Geri O]

Some of the Behringer DIs were prone to picking up noise from amps with big power transformers, such ash Ampeg SVT amplifiers. But I remember hearing that they had redesigned the DI to eliminate that problem. Just try moving it away from the amp and see what happens.

It could be the bass. Jazz basses with single coil pickups can pick up interference when use with both pups less than 100%. Does the hum stay there when you turn the pups all the way down, or unplug the bass altogether? If so, there's your problem.

The "ground lift" of the DI is meant to lift, or disconnect the shield from the DI. That should do it.

My last suggestion is my least favorite and least-recommended, but if absolutely nothing else works (including suggestions that someone else may offer besides me), get an AC ground lift adapter, available at Walmart or hardware stores, and put it on the power cord before plugging the amp in to the wall outlet. This sometimes solves the problem, but it's also dangerous because you've removed the amp's ability to protect you in case of an internal short (as in a wire carrying 120 volts laying against the metal amp chassis and somehow shorting to the chassis, making it live and potentially deadly. I'm ashamed to say, I've done it in a pinch until I could get the gear squared away with no hums or buzzes. I know many, many musicians that just leave these AC ground lifts on their gear all the time. That's scary!

And keep in mind that you may solve your problem in one situation, but it may crop up again. Different situations, building power, different PA gear, all can cause the hum and buzz potential to vary from gig to gig. You just to arm your self with a few things to help trouble-shoot and eliminate the hum and buzz when you run into it.

 

[NZBassman]

thanks for the reply
yes - it's a bit of a mystery this... I've been having problems for 3 years and when I sold my old Ibanez bass (active) and got the Squire (passive) the problem was solved for about a year, then it started randomly buzzing again.... but if I turned down the treble slider on my amp it disappeared - but then sounded crap on stage with no treble.
I bought the DI Box and used that and it was fine for about 5-6 months and 3 weeks ago drummer wasn't happy with the signal he was getting to the desk from the DI so we used his old kick mic and that worked fine. Last week used the DI and sound was ok, then this weekend just gone it started hissing again... we were playing in a Barn out in the country though, but no-one else in the band were having power / sound problems.
The only thing we haven't tried is plugging the bass direct into the desk to see if it is buzzing, but I doubt that will be the problem.

at this weekends gig I'll try and move the DI box away from the amp and see if that makes a difference and if not might plug my bass direct into the desk

 

[NZBassman]

Update – ok so set up at last weekends gig and use the DI box, and there is huge amount of hissing though FOH…. I then plug my bass direct into the desk (bypassing the amp and DI box) and there is no hissing – so bass is fine.
Drummer rummages his case with his drum / vocal mics in and pulls out an DI box (he didn’t know it was a DI box) so we puts a new battery in it and bingo… no hissing or anything – in fact guitarist commented that it is the best that my bass has sounded out front!!
So it seems that my DI box is faulty and not working properly. I asked guitarist after gig if putting a new battery in would make a difference and he said if the battery was dead then the DI box simply wouldn’t work – is this the case?
I don’t want to take the DI box back to the shop saying it is faulty, only to have them put a new battery in and get it working