WTH is that directional hum?

Trevorus · #1 10-25-2006, 12:48 AM

You know what I'm talking about? The hum that gets really loud when you face one way, but then completely disappears when you turn another way... How do I eliminate that???

CROZ · #2 10-25-2006, 02:32 AM

It's most likely from a flourescent light ballast or from a CRT monitor in the room you're playing in.

Some shielding on your bass will probably cut out most of it.

I had that same problem trying to record stuff on cubase when I had a CRT monitor and an unshielded j-bass.

Trevorus · #3 10-25-2006, 02:37 AM

using humbucking pickups, shielded, no ground loops. The hum only comes around noticeably when using high gain distortion... Which I like to use. So it's hard...

xyllion · #4 10-25-2006, 09:58 AM

Shield the pickup cavities and it will likely go away. Don't forget that you have to connect the shield foil to ground though.

vindy500 · #5 10-25-2006, 10:10 AM

Quote:

Originally Posted by Trevorus

shielded,

Quote:

Originally Posted by xyllion

shield the pickup cavities and it will likely go away. Don't forget that you have to connect the shield foil to ground though.

wow some people really listen

fourstringdrums · #6 10-25-2006, 10:14 AM

I know with my JB-2 I get hum if both pickups aren't at the same volume and only if I'm facing the amp. As soon as I turn away the hum stops.

luknfur · #7 10-25-2006, 12:26 PM

Quote:

Originally Posted by Trevorus

You know what I'm talking about? The hum that gets really loud when you face one way, but then completely disappears when you turn another way... How do I eliminate that???

FWIW:

I suppose if someone did a study they could distinguish flourescent from 60 cycle from electronics from defective power supply from whatever, noise is noise to me. 60 cycle will definitely do that however.

Bass is shielded, no flourescent light here, etc. and sometimes I get it sometimes I don't through too many setups to recall.

I'd say you answered your own question - in bold. On a more practical level, you can either figure out the source and resolve it or install active pickups - at least I've never had noise that I recall through active pickups though.

markjazzbassist · #8 10-25-2006, 01:32 PM

mine comes from my single coils and my CRT monitor. i need to get my axe shielded.

xyllion · #9 10-26-2006, 12:10 AM

Quote:

Originally Posted by vindy500

wow some people really listen

There is a difference between shielding the control cavity and the pickup cavities. Most basses have only the control cavity shielded, but don't bother to shield behind the pickups. Given what the original poster stated, it is not obvious that he means that the pickup cavities are shielded. Even if they are, they are not properly shielded if they aren't attached to a ground wire.

So, go attack somebody else.

Funky Doctor · #10 10-26-2006, 02:32 AM

I used to get that in a bass of mine where i forgot to connect the blend pot to ground. It did exactly what you are talking about. When I fixed the problem, it went away for good.

wpkg · #11 10-26-2006, 07:46 AM

Quote:

Originally Posted by xyllion

There is a difference between shielding the control cavity and the pickup cavities. Most basses have only the control cavity shielded, but don't bother to shield behind the pickups. Given what the original poster stated, it is not obvious that he means that the pickup cavities are shielded. Even if they are, they are not properly shielded if they aren't attached to a ground wire.

So, go attack somebody else.

"Shielded" to me means shielded. pickup and control cavities and all...

xyllion · #12 10-26-2006, 10:56 AM

Quote:

Originally Posted by wpkg

"Shielded" to me means shielded. pickup and control cavities and all...

I say that because very rarely do bass manufacturers actually shield the pickup cavities.

Atoz · #13 10-26-2006, 11:02 AM

I have that with my Ric at home, but I think it's more due to my crappy house wiring than anything else; since it doesn't really do that when I'm playing somewhere else.

Giraffe · #14 10-27-2006, 08:05 PM

You can easily tell the difference between RFI and 60 cycle hum using the process of elimination and a Jazz with single coils.

As for the position tricks, guitar players have been contorting and twisting and dancing around for years to find the "noise sweet spot" with their noisy teles and strats. A guitar player once showed me how to find the quieter positions, revolving the bass through a vertical plane, then a horizontal plane. He had the body language down to a fine art. He did not, however, have any explanation for why any of this happened. Neither do I.