Brand new Amstd J bass - humming problem

[Mapleleaf]

Hi everyone, - update - its a buzz not a hum , see latest post

I've got the dreaded humming problem that I've read about so much on here, and I am a bit concerned because my Fender Am Stad J bass is only a month old, bought new from local music store. I didnt notice it so much on my small practice amp ( roland bass cube) but I've just bought a new (ie brand new from the store) more powerful amp and the hum is really a pain. like most others have reported, it reduces when I touch any metal part of the bass or the strings, and when both volume pots are balanced it reduces. I cant really get the gain and volume where I'd like them without the humming intruding. I've tried moving locations, different power outlets etc but while it varies a bit in intensity its still there unless I turn down the gain/ volume combo.

My question is should this really be happening on a new piece of kit? Should this be something the music store/ fender should resolve for me or is it just the way these pickups are and I have to fix it myself - I didnt know before investigating on here that single coil pickups were prone to humming. No one in the store told me either ..

thanks

 

[joeyl]

well my am std jazz have shielding, so yours probably does too. Have you tried a different instrument cord and a different amp? Could be the amp since you did not have this with your cube?

 

[R. Laevinus]

Single coil pickups will hum. That's a sad fact of life. However, you can usually reduce humming to some degree via shielding, although I'd expect your AmStand is sufficiently shielded already.

The reason the hum decreases when both pickups are on full is that they are wired like the two coilds of a humbucker - but when the balance is changed, the hum will come back.

There are a number of products that might help - EHX makes a 'hum-debugger' pedal, and a noisegate pedal may work for you as well - however, I'd reccomend swapping out the pickups for noiseless if the hum is really bothering you.

Seymour Duncan makes a number of humbucking Jazz pickups, which are typically of a stacked design - however, the more high-end makers also make split-coil designs, which I'm told (I have never owned a J-bass) remain truer to the single-coil sound.

Check out www.bestbassgear.com for ideas on pickups models and how much they'll run. (I'm not affiliated with BBG in any way.)

 

[Mapleleaf]

thanks guys,

dont really want to change pups on a brand new bass ....

I'm going to the music store today so will try the bass in a couple of different amps so see if there is a difference and perhaps also try a couple of other basses too.

I'll ask them to check for shielding as well

 

[Mapleleaf]

Quick update: its not the humming that is my problem, figured out at the store that as mentioned by others on here that setting the volumes equal does indeed cancel out totally all humming. What it seems I have is a buzzing. Now at the store I tried a mesa 12" walkabout - full gain & full volume, all other tone settings set flat ( 12 o'clock) , both vol knobs on the bass on full , tone midway. Not one bit of buzzing was heard. touching the metal parts on the bass made no difference . So I tried a Mark bass 12 inch combo, same settings & again, no buzzing. I could induce & cancel the pickup hum by altering thevolume on one or other of the pickups. So its clearly not my bass that is the issue, which Definately pleased me.

Back home I tried more outlets, I even went to the outlet wired directly below the main fuse panel and got the buzzing on that and any others I tried - even a new sub panel from a new addition we had done recently, which passed electrical code & safety inspection. Buzzing started when the gain was turned up past 12 o'clock and volume anywhere past a quarter . Touching any metal part of the bass & strings stopped the buzz and also touching any metal part of my amp stopped it as well. With bass volumes turned off the buzzing stops and with the bass unplugged from the amp, no buzzing just white noise with gain & vol on full. So its not the amp. all tests were conducted ( Parden the pun) with no lights or other appliainces on in the room/ basement.

Looks like I have a "dirty" power supply to the house - the final test wil be to take the amp & bass back to the store & plug into the same outlet I tired today & see what happens. I'll let you know the outcome. The amp is a Mesa Carbine 6 2x12 combo - it has a value preamp but not sure if that makes any difference?

If it is the house supply that is causing the issue what can I do about it? is there any kind of electrical power cleaning device I can buy?

 

[Kipaste]

I'm pretty sure the bass will be completely quiet at the store.
Mine is similar; at some places, especially old buildings I get the buzz that goes away when metal is touched. Unfortunately, I've found less places where it's quiet than where it makes the noise. But in my home and in the studio I usually go to it's luckily dead quiet. You could try shielding your control and pickup cavities, to me it makes sense to start with that instead of doing some electronics overhaul on your house since the buzz is going to be way more annoying at a gig. I haven't yet shielded my pickup cavities since I figured I'd wait until yet another pair of new pickups arrives. Afterall, even preamp manufacturers like audere recommend doing that if you get that kind of buzz.

Here's a link to audere's troubleshooting page [Invalid or Expired Link Removed]

 

[Mapleleaf]

Thanks Kipaste, great link bye the way.
and you were absolutely right about the amp & bass being quiet at the store..

So they sent me away with a loan Furman power bar, but back home it made no difference that I could tell. After more experimentation, here is where I am at. on the Amp, Gain at 3/4 volume at 1/2, bass, both volume at full, Tone backed off completely . No buzz! as soon as I start to turn on the tone (anti clockwise) the buzzing starts and its at a constant level no matter where I then turn the tone knob. when I touch any metal part it stops. Turn down the tone completely and the buzz stops, touching the metal then has no effect.

before I start shielding everything is there anything that can be done with the tone pot to stop it causing the buzz? many thanks in advance

 

[David Jayne]

The noise you are hearing is airborn. The bass picks it up like an antennae. It goes away when you reduce the tone pot because it's a high-frequency noise. Your bass is operating correctly.
You could try to find the device that's causing it. It's likely to be an appliance of some kind in your home, but could be caused by nearby high-voltage power lines, radio towers, etc., in which case there's really nothing you can do.

 

[joeyl]

do you have dimmer switches nearby?

 

[SGD Lutherie]

Single coil pickups will hum. That's a sad fact of life. However, you can usually reduce humming to some degree via shielding, although I'd expect your AmStand is sufficiently shielded already.

Shielding helps with electrical field noise, which is the high pitched buzz you hear, but it does not get rid of magnetic field hum, which is what you get with single coils.

All kinds of stuff cause buzzing... light dimmers, CRT monitors, etc. I was rehearsing in someone's basement, and we all had this crazy buzzing going on, even through my bass' humbuckers. It turned out the guy had one of those "invisible electric fences" for his dogs! That was creating the noise.

 

[Mapleleaf]

i do have dimmers and have experimented with them - and yes they do interfere - you can get some weird spacey sounds thru the amp turning the dimmers up & down However, i was able to kill them at the breaker but the buzzing was still there from somewhere else

I have been able to differentiate between the single coil hum & deliberatly induce it by having the volume pots at different levels - but that isnt all that intrusive compared to the buzzing . The store manager has arranged for me to take the bass back on Monday for their tech to check & if needs be fix the grounding. He thought that is was "just a grounding issue" & commented that the store was effectively designed electrically to have no interference issues at all - makes sense i suppose as they would no doubt have a hard time selling kit that buzzed .

edit : I took off the pick guard and control plate and it looks like the cavaties are shielded with paint and then the bass body colour spayed on top - apart from where a ground wire is screwed the body and to the grey shielding paint - that was the only sign of factory shielding.

I'll report back Monday - thanks for the input so far.

 

[Mapleleaf]

so i took the bass back to the store and the tech checked it over and declared that all was well grounding wise . basically nothing faulty & handed it back to me - I had already tested the ground and got almost zero ohms between varous ground points incl the shield paint so half expected this outcome. All that is left now is to order a shield kit from probably stewmac (or just play at lower volumes at the house... but thats no fun ).

thanks again to everyone who chipped in.

 

[SGD Lutherie]

You need to check the grounds at your AC outlets at your house. Also sometimes these ground buzz issues are at the amp. If you put the bass on a stand and reach over and touch a metal part on the amp, and the buzzing stops, it's a ground issue at the amp end. Are you plugging your amp into one of those 3-prong ground adaptors?

 

[Emanuel Apascaritei]

I have an AmStd Jazz too and the only problem with buzz I have is when I get really close to the amp and have one pickup lowered (mainly the neck pickup)