Humming - cable related??

backer_bassist · #1 09-15-2008, 02:47 AM

Not sure if this is the right place to post this.

I run an Ampeg 15" cab with an ampeg B2R head...
I also have a Behringer Rack tuner and use an Electro-harmonix Russian Muff. The Problem is my amp "hums".

i notice it gets louder when turning the highs/trebles up and gets quieter turning the lows up... (on my bass guitar)...

i recently found out it was a fire hazard among other things to connect your amp head to your speaker with instrument cables and because i WAS doing this.. i thought that may have contributed to the hum.. but i have just bought some speakon cables and the hum is still there... it hums whether the fuzz is plugged in or not...

im not quite sure what to do to eliminate this... help!!!
all i can think to do is to quieten it by using the PAD on my head... argh!

Deacon_Blues · #2 09-15-2008, 07:02 AM

Is the hum the same with different basses? Many basses do hum a little. I'm not sure if you can eliminate it all without spending money on new pickups and electronics. If you have the possibility to check out different basses, active and passive, do it. Anyway, before that, disconnect any effects and tuners and plug straight into the amp with a good cable, preferably a rather short one and check that it's not lying next to a transformator or along power cables, that may cause some humming.

Travisx2112 · #3 09-15-2008, 08:46 PM

Do you have your instruments cable crossing with any power cables? That causes humming.

Zooberwerx · #4 09-16-2008, 05:43 PM

All good suggestions. When I hear something described as a "hum" and not a "hiss", I start looking for grounding anomalies (e.g. ground loop). Could be the bass, cables, head, etc....you'll just have to substitute each component one-by-one to pinpoint the source.

Riis

backer_bassist · #5 09-16-2008, 11:31 PM

i play an American std J bass... and i think ive put it down to the pickups... ..all my leads are fine... tried plugging straight into the amp head and it still hums also..

the fender nerd at my local told me he can re-wire my pickups to stop the hum... is it really worth it? has anyone done this to theirs? im just not sure

JimmyM · #6 09-17-2008, 12:43 AM

That's a real tough call. If you use both pickups full on, or if you keep their volumes dead even, a Jazz won't hum. But if you don't, they can often pick up hum. You can use humbucking pickups, but you may or may not like the character of the tone when you switch. A lot of people leave the single-coil pickups on because they don't want to mess with the character. I left my old 98 MIA's pickups on because I didn't want to mess with the sound. I've changed them out on other basses, though.

So before you go changing things, you should try to play a Jazz with humbuckers first.

Deacon_Blues · #7 09-17-2008, 07:38 AM

Yes, there's humbucking pickups with the same size as a normal single coil jazz pickup. At least Bartolini makes them. I once ordered a set of them for a Warwick I used to own, and they seemed to work pretty well as intended.

dwanetom · #8 09-17-2008, 08:40 PM

Does this happen only at only one location (house, club, etc.) or every location at that you play. If it only happens at one location it's probably the house electric circuit, which is probably in need of updating. There is one club I play at where I have to sit sideways to eliminate the hum. It's the same location where I get radio signals coming through the amp.

backer_bassist · #9 09-21-2008, 08:03 AM

Quote:

Originally Posted by dwanetom

Does this happen only at only one location (house, club, etc.) or every location at that you play. If it only happens at one location it's probably the house electric circuit, which is probably in need of updating. There is one club I play at where I have to sit sideways to eliminate the hum. It's the same location where I get radio signals coming through the amp.

nah it happens at ALL locations... i dont want to change the sound of the bass either... im not too keen on changing pickups or rewiring... will a noise gate stop it or not??

lethargytartare · #10 09-21-2008, 10:31 AM

Does the hum go away when you touch the strings of your bass (or the bridge)?

Are you the original owner of the bass, or has anyone done any work on the wiring itself?

IIRC, the tone control on a standard bass is just a treble-cut, so when it's "up" you're just hearing the full level of the noise, but when it's "down" (bassy) you're cutting a lot of the frequencies that cover that noise...but that aside...

If the hum goes away when you touch the strings, it's something that could be improved with some wiring changes. Zoober is right that ground loops are one of those issues that lead to hum. And that's also why I asked if anyone has messed with the wiring yet -- if so, it's possible they missed a ground wire, or created a ground loop, etc.

There's a great DIY site about this -- guitarnuts.com -- and that guy explains that your body is basically a huge antenna that "collects" noise from the surrounding area, and (again, IIRC) radiates it near your strings, creating noise that gets right into your signal. But, if you touch the strings, and your bass is wired correctly, you shunt all that noise to ground (since your strings touch the bridge, and there's a wire under your bridge that is connected to the ground lug on the output jack which, by way of the instrument cable and amp, connects to the buildin'gs electrical socket's ground).

If the noise is constant regardless of whether you're touching the strings, then maybe you have an actual problem in there. Is there any chance your output jack has gotten loose at times, and might get twisted around? Might be that the ground wire on the jack got frayed and isn't connected properly.

Can you take pics of the electronics and post them?

backer_bassist · #11 09-22-2008, 02:51 AM

im the first owner of my bass... its a MIA jazz bass.. and its only 3mnths old.... :s

lethargytartare · #12 09-22-2008, 08:16 AM

How about the strings -- does the hum go away when you touch the strings?