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Bass hum, who's responsibility?


bassix
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I'm not sure there is a definitive answer to this but here goes. Purchased a new p bass 2 weeks ago and it has been perfect until last night it developed an uncontrollable humming. I tested the amp and cable with another bass which had no hum so I'm assuming this is an issue with the bass itself. The question is do I have to fork out to get the problem resolved myself or am I justified in asking the shop to fix it?

To be clear, I do not want it replaced as I chose this one from the available stock.

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Take it back to the shop. If they don't want to know, remind them of the "Sale of goods Act". The SOG Act says all goods must be "fit for purpose" and if it hums then it's not fit for purpose. You could also tell them on day one, that if you don't get it resolved within 30 days you want a refund. Then you've also set them straight about your expectations from the beginning. This saves arguing about it later.

Good luck

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is the hum constant all times or does it change when you touch strings or any other metal parts?

is the jack fitting snugly into the socket

could be an easy fix if its a loose wire or bad solder joint somehwere if you are confident to fix yourself otherwise back to the shop if all the control plate needs looking at and/or bridge plate might need lifting to check the ground contact underneath

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When I play any bass in my sitting room with an amp there's an annoying hum. If I move the amp elsewhere in the house it disappears. It can be due to the electrical wiring surrounding you where you are playing, rather than to the bass itself. Is this a possibility? If not, agreed -go straight back to the shop

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Thanks for the responses, to answer a few of the points, I did try moving the amp to another room and the hum was at the same level. With regards to the hum when touching the strings it stops, it is also almost entirely absent when the tone is rolled completely rolled off. I have looked at fixing the issue myself but I almost feel like I shouldn't have to on a bass that is essentially brand new. If the hum had been there when I bought it then I wouldn't have such an issue but there has been a clear change from when purchased to now.

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[quote name='Ou7shined' timestamp='1378973925' post='2207119']
Sounds like your bridge/earth wire has come owft. 5 minute fix.
[/quote]

Nope! If the hum goes when he touches the strings the bridge ground must be making good contact.

From what i read i would say that the problem is lack of shielding on the bass. Isolate the electronic cavity and the back of the pickguard with some copper foil and the humm will go away.

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[quote name='bassix' timestamp='1378972465' post='2207096']
Thanks for the responses, to answer a few of the points, I did try moving the amp to another room and the hum was at the same level. With regards to the hum when touching the strings it stops, it is also almost entirely absent when the tone is rolled completely rolled off. I have looked at fixing the issue myself but I almost feel like I shouldn't have to on a bass that is essentially brand new. If the hum had been there when I bought it then I wouldn't have such an issue but there has been a clear change from when purchased to now.
[/quote]

P basses are very well known for this issue, it's not a faulty unit. Read my last post and get someone to shield your bass. Maybe the guys in the store could offer you that service but keep in mind that it can't be seen as part of waranty. the bass is like that out of the factory..

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[quote name='Ghost_Bass' timestamp='1378977219' post='2207187']
Nope! If the hum goes when he touches the strings the bridge ground must be making good contact.

From what i read i would say that the problem is lack of shielding on the bass. Isolate the electronic cavity and the back of the pickguard with some copper foil and the humm will go away.
[/quote]

Don't you just hate it when a bass is fine for weeks then suddenly overnight the shielding lacks.

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[quote name='Ghost_Bass' timestamp='1378977219' post='2207187']
Nope! If the hum goes when he touches the strings the bridge ground must be making good contact.

From what i read i would say that the problem is lack of shielding on the bass. Isolate the electronic cavity and the back of the pickguard with some copper foil and the humm will go away.
[/quote]

This is completely wrong - if the strings were properly grounded then touching them would make no difference, as they'd already be at ground potential.

Touching them is proving an (indirect and high resistance) path to ground, via your body, which is enough to attenuate the noise, which is probably induced noise from electromagnetic interference (TV, lights etc) on the strings and other metal parts of the bass.

An earth must've fallen off inside the bass, or possibly the cable has a dodgy shield so I'd try a new cable first.

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Well, i think i didn't explain myself properlly so here goes.

If the hum stops when the hand touches the strings then the ground is connected to the bridge or it wouldn't make any difference at all.

Hum can be caused by radio interference and a shielding not only acts as a shield for RF freqs but it also provides a better grounding to the bass.
I maintain my solution of a copper shielding in order to solve this issue of the bass.


I can be a ground wire working itself loose in the pot connections but with shielding all pots and jack automaticly ground themselfes to the copper on the back of the pickguard so this will make the same effect of unsoldering and resoldering all grounds (and that wouldn't solve RF interference issues...)


Cheers

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[quote name='6v6' timestamp='1378979733' post='2207225']
This is completely wrong - if the strings were properly grounded then touching them would make no difference, as they'd already be at ground potential.

Touching them is proving an (indirect and high resistance) path to ground, via your body, which is enough to attenuate the noise, which is probably induced noise from electromagnetic interference (TV, lights etc) on the strings and other metal parts of the bass.

An earth must've fallen off inside the bass, or possibly the cable has a dodgy shield so I'd try a new cable first.
[/quote]

Not this again.

Noise goes away when you touch the strings because you're grounding *yourself* not because you are grounding the strings.

The human body is a massive antenna for unwanted electrical noise. This noise is picked up by poorly shielded pickups and so you can hear it. When you touch the strings you ground yourself and the noise goes away.

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Suggest you
1. Take the bass to a friends house and try it there with a fresh cable and amp. Turn off any lights

2. Try it there with your cable and then your amp
See if the problem stays

If you still get the issue you probably have a wiring fault or need shielding, but I never needed shielding on a p bass

There is a whole sticky thread on this topic. Suggest you get copper foil with conductive glue as its a lot easier

Edited by Geek99
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[quote name='bassix' timestamp='1378972465' post='2207096']
Thanks for the responses, to answer a few of the points, I did try moving the amp to another room and the hum was at the same level. With regards to the hum when touching the strings it stops, it is also almost entirely absent when the tone is rolled completely rolled off. I have looked at fixing the issue myself but I almost feel like I shouldn't have to on a bass that is essentially brand new. If the hum had been there when I bought it then I wouldn't have such an issue but there has been a clear change from when purchased to now.
[/quote]

It's most likely an earth wire issue as P basses are usually pretty silent when wired correctly as the pickups are humbuckers. The following diagram shows what the wiring should look like, If you're curious unscrew the scratchplate and have a look, The earth wire (which comes from under the bridge) should be soldered to the volume pot. If it's not then that's what's causing the buzzing. If everything seems to be soldered correctly then it's a more serious matter. Either way I think you should take it back to the shop and ask their tech to fix it,since you bought it from new. [url="http://www.buzzardsbass.com/electronics/wiring/diagrams/pbass-std.jpg"]http://www.buzzardsbass.com/electronics/wiring/diagrams/pbass-std.jpg[/url]

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Thanks for all the responses. To cover off a few of the points raised: I tried the same setup with another bass (ie same cable, same amp) with no humming, this says to me that it is solely a problem with the bass and not the associated equipment. Secondly, the humming was not present when I bought the bass, it is something that has developed yesterday, 10 days into ownership oddly.

I have seen the threads on how to fix the issue but it strikes me the bass should not be in this position after 10 days of ownership and it almost certainly should not be my responsibility to correct if it fails in that time frame.

I will be returning it to the shop for hopefully a simple fix on their part and I can go on enjoying the bass. I hope they will agree to this because I really don't want to get my money back and have to restart the search for "the one".

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Taking it back will be your safest bet.

P basses are a big pita for this, which is why I go for basses that have properly shielded basses with hum cancelling pups :)

Btw, even shielding all the cavities might not fix 'noise'. But I agree with Ou7shined that it sounds like a grounding issue.

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