Help With Wiring

[ballcapdan]

Ok, here's my problem:

I replaced my stock peavey jazz bass pickups with EMG selects. I was told by several people that the new pickups were humbuckers, so I should use 500k pots. As the old ones were 250's, I ordered three from Stewmac, along with a new capacitor. Tonight, a friend and I wired it all up. Problem is, unless both volume pots are all the way up, I get a nasty buzz. If the volumes are up, I can play with the tone. If I mess with the volumes, I have to turn the highs out of the tone to get rid of the buzz. Also, the buzz would change as a moved the guitar around. Softer then louder.

We followed the diagram supplied with the pickups, and can't see any problems with how things were soldered, but obviously there is one. Could we have damaged a pot by getting it too hot? Also, the solder had a hard time sticking to the pot. He scratched the surface to expose bare metal on each.

Any ideas?

[lovekraft]

Sounds like you've got a grounding problem - try rewiring so that all the ground leads, including the bridge ground, the output jack and any shielding, hook up at one spot, and check to see that your solder joints are all good. If you're worried about the pots, check them with the multimeter.

BTW, you're not standing next to a computer monitor, are you?

[crafty]

Yeah, check the ground continuity on everything, but also double-check the resistance of those pots through their full sweep. If you had a hard time getting the solder to bond then you may have held the heat on too long and burned up the pot.

For future reference:

1. Clean corrosion off surfaces to be soldered with a pencil eraser, even if you can't see corrosion.

2. Clean eraser residue off surfaces to be soldered with rubbing alcohol.

3. Set your soldering iron for medium heat.

4. Tin the soldering tip and wipe clean with damp sponge.

5. Tin the surfaces to be soldered.

6. Solder the components together with quality rosin-core solder. The stuff at Radio Shack is crap, but short of buying the good stuff from Jameco or Jensen, look for it at Sears. It's the best stuff I've been able to find locally and it melts and flows just as good as Kester. I also like using paste flux to aid soldering of large areas, but it can mess with the innards of components like potentiometers.

[blackburncustomguitars]

By the way, you might have already thought of it, but be sure each pot is grounded as well.

Ok, here's my problem:

I replaced my stock peavey jazz bass pickups with EMG selects.  I was told by several people that the new pickups were humbuckers, so I should use 500k pots.  As the old ones were 250's, I ordered  three from Stewmac, along with a new capacitor.  Tonight, a friend and I wired it all up.  Problem is, unless both volume pots are all the way up, I get a nasty buzz.  If the volumes are up, I can play with the tone.  If I mess with the volumes, I have to turn the highs out of the tone to get rid of the buzz.  Also, the buzz would change as a moved the guitar around.  Softer then louder.

We followed the diagram supplied with the pickups, and can't see any problems with how things were soldered, but obviously there is one.  Could we have damaged a pot by getting it too hot?  Also, the solder had a hard time sticking to the pot.  He scratched the surface to expose bare metal on each.

Any ideas?

←

[thomasteven]

If your old pickups were not humbuckers, they probably weren't as "hot" which means there is a lot less buzz or static noise, this isn't always true though. Humbuckers tend to be a higher output, or "hotter" than single coil, so they naturally tend to buzz a bit more.

But like everyone else said, check your grounding and make sure that they all lead to a common ground point.(you need to ground your pickups, pots, switches and your jack)

[lovekraft]

Humbuckers tend to be a higher output, or "hotter" than single coil, so they naturally tend to buzz a bit more.

No, that's why they're called humbuckers - all other things being equal, they're inherently quieter than single coils

[thomasteven]

I always found humbuckers to buzz or hiss a bitmore than single coils.

[ballcapdan]

Thank you all for the help.

Everywhere I read, and everyone I asked said it was likely a grounding problem. So, I thought I would check those. After looking at it though, I decided it would be easier to just take everything apart and start over. So I did. And it worked. I honestly couldn't say what I did differently this time, except to be VERY carefull about what was touching what and where. Thankfully it worked.

The new pickups sound much better than the stock ones. More defined and a lot quieter (maybe because of the shielding). After doing this though, I realized something (everyone else already knows this I'm sure). The tone pot doesn't really change the tone, as much as it sends certain frequencies to ground, as determined by the cap. A filter of sorts. Sorry for stating the obvious, but it was a revelation to me..................

Next will be an active system.

Also, some guitar store repair guy told me that it doesn't matter what value of pot I use, because I wouldn't be able to hear the difference, regardless of the pickup type. Any comments on that?

Edited January 29, 2005 by ballcapdan

[lovekraft]

Glad you got it sorted - ignore the repair guy, you can definitely hear the difference between 250K and 500K pots with just about any passive pickups (unless you've got the high end dialed completely out of your amp). In active systems, tone probably won't be affected, but the response to turning the knob may get weird ( using a 500K with EMGs makes the volume act more like a switch - very little change, then off).

BTW, thomasteven, the whole point of humbuckers is to eliminate 60Hz buzz/hum, along with any induced noise from fluorescent lights, transformers, etc. - if you're getting more hum out of humbuckers than singles, you're doing something wrong.

[crafty]

If your old pickups were not humbuckers, they probably weren't as "hot" which means there is a lot less buzz or static noise, this isn't always true though. Humbuckers tend to be a higher output, or "hotter" than single coil, so they naturally tend to buzz a bit more.

What on EARTH are you talking about?!

Hum-buck-ers "buck" the "hum". Single coil pickups do not. That post makes absolutely zero sense. Either that or we just have completely different perceptions of what buzz sounds like.

[lovekraft]

There must be an echo in here - I could have sworn I've heard that before!

[crafty]

There is no echo. You used your insidious mental telepathy skills to read my thoughts and post MY comment before I did. I couldn't let you get away with that!

Seriously, though, I've only had one humbucker buzz on me and that was because of a poor braid connection to ground. I resoldered that and only had problems when I was next to a computer monitor, which I've found that not even EMGs can block that kind of interference.

[thomasteven]

I've found my problem! Whenever I play it's in front of this very screen so that's probably why it humms or buzzes or does whatever it does.

Solution through mistake!

[lovekraft]

Yeah, that'll do it! I'm not sure an industrial-strength Faraday cage will work if you're standing next to a monitor.

Been there, done that, moved my amp!

[G_urr_A]

I just thought I'd offer my input on the computer monitor issue.

I can get almost buzz-less with my strat clone (3 singlecoils) sitting right here, less than 2 feet from one 17" and one 19" monitor. Requires some positioning of the guitar, but it's certainly doable.

[Edit]

And that's with rather heavy distortion on. But obviously there's a noise gate involved too.

Edited January 30, 2005 by G_urr_A

[crafty]

But obviously there's a noise gate involved too.

You are a master of the obvious. Thank you.