Bad Grounding problem?

JoeDissolvo · #1 08-14-2010, 01:04 AM

Ok, since the search function failed, ive got a question.

I played at a new venue tonight, and i plugged in, turned everything on like i usually do, and get an annoying sound like a very loud bat has taken up residence in my bass amp. I quickly turn it off, check all connections, and try it again. Same thing. I turn down the master volume and gain, and turn it back on. Its STILL doing it. I swap out my cable for another one i have with me, and its a little better. But i still had to smack the cable every once and a while when it started to buzz, or rest against my bridge. I know everything amp/bass wise is good, we just practiced last night with the same set up, with no problems with my rig.

The place was set up pretty shoddy anyway, tons of extension cords and surge protectors everywhere. Ive ran into slight buzzing from a grounding problem before, but nothing like this. Not even close. Just wondering if anyone has any insight on it. Does it sound like the place was badly grounded, or is it something else i need to look into?

billfitzmaurice · #2 08-14-2010, 06:41 AM

Quote:

Originally Posted by JoeDissolvo

Does it sound like the place was badly grounded, or is it something else i need to look into?

The most likely sources of the buzz are flourescent lighting and/or cheap dimmers, the most likely transmission point of the buzz is via RFI through your pickups, and aside from removing the source of the buzz there's nothing you can do about it.

jnewmark · #3 08-14-2010, 06:56 AM

Would this work ?

http://www.radioshack.com/search/ind...i%20choke&sr=1

Foz · #4 08-14-2010, 06:59 AM

try a new guitar cable(s)... a small flaw in the shielding can make a difference in a noisy environment = what seems a good cable in a normal place acts like a bad cable in a place with lots of RF bouncing around. Like Bill sez its still gonna be sub optimal - the only real cure is to tighten the venue up - but it might help a bit and worth a try IMO.

billfitzmaurice · #5 08-14-2010, 07:10 AM

Quote:

Originally Posted by jnewmark

Would this work ?

http://www.radioshack.com/search/ind...i%20choke&sr=1

No. You have to stop the noise at the source.

Jerrold Tiers · #6 08-14-2010, 07:24 AM

Generally you cannot stop the noise at the source, and you HAVE to make the amplifier more resistant.

The causes of the problem are, in rough order of probability:

Bad cable

Guitar not shielded well

Amp not very resistant to noise and radio pickup.

If the amplifier has plastic input jacks, it is usually more sensitive to noise pickup than amps with metal sleeve jacks, although that is not always the case. A good, intelligent tech can often install a few parts which will not affect the sound, but will reduce the problem if not eliminate it. I found that usually just two parts would go a long way towards curing the problem.

Foz · #7 08-14-2010, 08:02 AM

Quote:

f...usually just two parts would go a long way towards curing the problem.

I'll bite... is one em better input jacks?

JoeDissolvo · #8 08-14-2010, 08:47 AM

Thanks for the help everyone. But it wasn't a buzzing as much as a squelching feedback. It does have a metal connector to the head itself, and the bass is pretty well sheilded. I think I might chalk it up to stupidity or horrible electrical there.

As I look back on it, I think it might have been personal stupidity. As I was turning everything on, the mic for my rig was only about 6 inches away from the front of my bass. Ugh.

I'll report tonight after our show at a slightly better venue. I hope its nothing too bad.

JoeDissolvo · #9 08-14-2010, 10:27 PM

Yep. Just a horrible condition at the venue. tonight everything went fine, and sounded awesome. Darn crappy venues.

bassandsurf · #10 09-16-2010, 03:08 PM

I have a rehersal studio in my bed room for my covers pop band. I plug a lot of stuff in my 220v wall plug. a yamaha amplifier with cabinet for keybords and voices, a laptop, a firewire audio interface, a dbx 163x compressor, a yamaha keyboard for midi sounding, and a bass guitar combo amp 12". yesterday using all the equipment for the first time my combo bass amp started makeing weird noises like if a bat was stuck inside the cabinet. I freaked out, started shutting down the pc, the interface, the whole plugs from the wall and still make that sound.
the answer was in the plug to the wall from the amp. I changed the ac power chord from one plug of the wall to another one that seems to be in another electrical cirtuit of my building.

this helped and everything is back to normal.

I was thinking I might be needing a current stabilizer for all that equipment.

I'm from argentina so pardon my english, if this post doesn't make sense, please tel me and I will try to put more detail in it for your comprehension.

cheers!