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Jazz Bass--noise when pickups at different levels

D

dzielonka

Dec 11, 2008
10
0
#1
Hi all,

I just got a Squier Vintage Modified Fretless Jazz bass. I'm loving it, but I have the standard issue of a good deal of noise and buzz when the pickups are set at different levels. I have a super simple set up...pretty much a new guy to all this. Small practice amp and the bass. If I get a Boss NS-2 or something like that, will it eliminate the noise generated by the differing pickup levels? Will that noise be present when I play though, or just eliminated when I'm not playing but plugged in?

Thanks all,
David
 
#2
David,

That's normal behavior with single-coil Jazz pickups. Together they cancel hum, but if the levels are not the same on both pickups they start picking up hum.

You can help this somewhat by making sure the bass is properly shielded from the electromagnetic interference that causes the hum (see the "Jazz Shielding Pictoral" at the top of this forum). A noise gate like the NS-2 cuts the output when the signal goes below a certain level, so it will get rid of the hum in between notes, but won't do anything about the hum while you're playing. You can also replace the single-coil pickups with humcancelling pickups, though that may change the sound. I'd try shielding first.

Mike
 
#3
Thanks Mike. That confirms much of what I've read. I do want to keep the sound of the single-coil pickups so shielding will have to be done at some point. Unfortunately I'm not really much of an electronics guy so I may take it to a shop.

Anyone out there know of particularly good guitar repair/set up folks in or near San Francisco.
 
#4
From what I'm reading, this Rocktron Hush Noise Reduction Pedal is different from the NS-2 or the ISP Decimator. Anyone have practical experience with it as relates to the jazz bass pickukp issues I mentioned earlier in the thread?

Thanks!
 
#5
dzielonka said:
Thanks Mike. That confirms much of what I've read. I do want to keep the sound of the single-coil pickups so shielding will have to be done at some point. Unfortunately I'm not really much of an electronics guy so I may take it to a shop.

Anyone out there know of particularly good guitar repair/set up folks in or near San Francisco.
Click to expand...

Its not that difficult, if you're in the mood. There is no need to solder anything, if you don't want to. Remove the strings, then remove the pickguard and remove the screws holding the pups, leaving the pups, for now, in the cavities. Remove the knobs and nuts/washers from the pots in the control cavity, then remove the control plate. Lift all the electronics out and set it aside. There will likely be a ground wire coming from the bridge that will limit how far away you can set it, however. Remove the foam rubber or whatever the pups were resting on in the bottom of the pup cavities.

Before doing all of this, you will have ordered/gotten your hands on some copper tape. StewMac, Carvin, other parts places sell it. Maybe you can find it locally, I wouldn't know.

Cut the tape with scissors and stick to the inside (all sides and bottom) of the cavities (pickup and control). Make sure each piece of tape overlaps a little onto the adjacent piece to maintain electrical continuity and avoid having to solder. Another way to avoid soldering is to allow the tape on the sides to extend a little over the top edge and onto the body around the cavities. After the cavities are all covered in copper tape, cut a big chunk of tape the size of the pup cavities (combined areas) and place it on the back of the pickguard. Cut out the holes where the pups will extend upward and thru. The tape on the back of the pickguard (and the already metal control plate) will make contact with the tape that extends slightly out of and onto the top of the body from the sides of the cavities will contact each other and cause the whole thing to be shielded without soldering. For that matter, you probably really don't need to remove the pots from the control plate and can actually just remove the entire assembly with the pots still attached to the plate. The only thing to watch out for is that ground wire that generally runs from under the bridge to the input jack. Hopefully it will be long.

Someone let me know if I've forgotten something...
 
#6
A noise gate cuts the noise when your not playing...
There is really nothing that you can do to cut the noise when you are playing.

If you screw around with a good parametric eq, you may be able to suppress some of the noise a bit, but you wont be able to remove it without severely altering your tone.

Try to keep your bass away from things that will make the noise worse, like computer monitors or flourescent lighting
 
#7
Thanks Jo. It is the soldering and fussing with existing wiring that I want to avoid. But if I can shield it and leave the wiring in place then I might give it a try myself. I do have new strings coming so I'll be changing those soon anyway.

I'm just fussing this much because I want to take advantage of the tonal variety some. Obviously I'm pretty new to it. My other bass is a Peavey Grind with humbuckers but I love the sound of the two single coil jazz pickups.

I'll take any other advice that's out there. This is a great site.

Thanks again.
 
#10
It may be easier to use conductive shielding paint, also available from the same suppliers. You can probably paint the cavities without disconnecting any wires.

The paint isn't quite as good as the copper foil, but it does make a difference.

Noise gates can be tricky; they can affect the attack of a note. Sometimes you can hear the gate opening/closing, which is terribly distracting.
 
#11
dzielonka said:
From what I'm reading, this Rocktron Hush Noise Reduction Pedal is different from the NS-2 or the ISP Decimator. Anyone have practical experience with it as relates to the jazz bass pickukp issues I mentioned earlier in the thread?
Click to expand...
Yes, and the answer is that noise gates from every manufacturer are a bad band-aid at best. Also FWIW Rocktron's Hush and the ISP are a lot more similar technology than either of them let on in their advertising.

My personal choice of compromise (because it's always going to be a compromise of some kind) was pickups which had good tone yet were hum-canceling, plus thorough shielding. My favorite pickup for this is a Nordstrand, my second favorite is the Fender SCN.
 
#12
Thanks everyone for all the good advice. I'm going to take some time on making dramatic changes since I just picked it up and at this point don't want to put as much into it as I paid for it. The new split coils sounds promising, but first I think I'll just try the shielding and see where it all goes from there. I'm still open for any tips. I'm just learning about all this stuff right now.

Thanks.
 
#13
The shielding is a good call but be careful with that copper tape as you lay it into the cavities-it can cut you badly. Seriously.
Pickups? Split coils from Nordstrand are excellent, as suggested. But they won't sound quite the same. Very similar, but different. Many would say 'not as good.' Just so you know.
 
#15
I picked up a Squier VM fretless two nights ago. Took it to practice last night, but getting alot of hum/noise. I'm going to do two things to fix this.
1) DI with ground lift. The PBDDI I was using doesn't have a ground lift :(
2) shield the bass

I've got plenty of shielding material and I'm ready to go.

Question. My Squier VM fretless (black) ground wire from the bridge connects to the bottom of one of the pots, not the input jack. There is only one (red) wire connecting the input jack. Is it grounded thru the control cavity plate?

IMG_1365.png
 
#16
dzielonka said:
I do want to keep the sound of the single-coil pickups so shielding will have to be done at some point.
Click to expand...

I hate to break it to you, but shielding wont get rid of single coil hum. If it did, they would have already done it on your bass.

The 60/120 Hz hum is caused by magnetic fields from things like motors and transformers. The only way to get rid of that is with magnetic shielding. But if you did that the pickups wound not be able to sense the strings moving over the magnets!

The other source for noise is electrical fields. This is what electrostatic shielding helps with. That type of noise is the high pitched buzzing you sometimes hear.

One other thing. Some people wrap copper or aluminum foil around the pickups. This can help with the electrical field noise, but if you wrap a closed conductive loop around the pickup, you will lose some high end. So the foil needs to have a break so it doesn't form a loop. And all shields must be grounded!

If you really want a quiet bass, there are many fine sounding hum canceling Jazz pickups that sound very much like the original single coils. The small differences in tone between the two are lost in the mix anyway. ;)
 
#17
tedsalt said:
1) DI with ground lift. The PBDDI I was using doesn't have a ground lift :(
Click to expand...

That has nothing to do with the noise from your pickups.

Ground lifts are for eliminating ground loops between your amp and a PA system.


2) shield the bass

I've got plenty of shielding material and I'm ready to go.
Click to expand...

See my post above. It will get rid of some noise, but not the hum from the pickups.

Question. My Squier VM fretless (black) ground wire from the bridge connects to the bottom of one of the pots, not the input jack. There is only one (red) wire connecting the input jack. Is it grounded thru the control cavity plate?
Click to expand...

It is grounded through the control plate, and that's a poor practice. This saves them from having to solder one more wire. You should solder a ground wire from the back of the pots to the jack. If you jack got a little lose, or if the plate gets oxidized, you would lose your ground connection!
 
#18
Thanks David. I think I had issues with both Thursday evening. I'll check into noiseless pups down the road. I went ahead and shielded the cavities, tying the shielding together with wire and overlapping under the control cavity cover. I'll tighten my input jack (I think it was a little loose).

It sounds good at home, but it always has. Test will be tomorrow hooked up to my church's system. Sound guys spent almost the whole rehearsal time Thursday trying to fix the hum/noise problems. The Sansamp PBDDI I was plugged into doesn't have a ground lift, so there may have been problems there. Even with nothing plugged into it there was hum. When they unplugged the PBDDI the hum was gone. I've got a couple of DIs with ground lift I'll take. Hopefully this will all be more hum/noise free tomorrow!
 
#19
I replaced with Hot Stack Jazz pups and it did the trick but I have to admit I am a bit unhappy about the trade off. I believe the original pickups were good enough. Now I believe I should have invested in an onboard preamp.

You may want to try these modded tone pots like the ones EMG or Stellar (?) make.
 
#20
If I went noiseless, I'd prolly look into the Fralins or the Nordies. I've heard good things about both. Preamps are always good, but that might involve routing out some space in the body. Either of these will take time and money, so this may turn into a longer term project.

I need to finish my old Spector NS2A electronics revamp first :D Same pups it had (like 'em; don't think they're stock when I bought it), OBP3, new pots, etc.
 

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