Need help wiring a bass guitar asap!

Jim Cohen · Post by **Jim Cohen** » 25 Apr 2003 6:57 pm

I'm faking my way through a few tunes on bass tomorrow and have a cheapo bass guitar but it doesn't seem to be wired up correctly. It has two split pickups and two knobs. I'm not sure if the two knobs are supposed to be one for volume (of both pickups) and one for tone (also of both pickups) or if one knob is for one p/u and the other for the other p/u. In any case, one knob seems to do nothing and the other one makes things louder and fuller, but never shuts off volume completely. I think it's screwed up in the wiring. I've opened the back and can access all the wires but I'm not sure how it should go. Anybody out there I can talk with by telephone tonite (Saturday) who can walk me thru this? You can phone me toll free till midnight east coast time (1 hr. to go!) at 1-888-355-4103. Thanks!
Jim

Michael T. Hermsmeyer · Post by **Michael T. Hermsmeyer** » 26 Apr 2003 12:07 am

Hi Jim, I hope I'm not too late.
Check Stewart Macdonald's website for free printable wiring diagrams. www.stewmac.com

Here is the link you want http://www.stewmac.com/cgi-bin/hazel.cgi?action=SERVE&sku=I-0032&s1=Free_info_sheets&item=freeinfo/fi.html

If that doesn't work, I will give you some suggestions on wiring.

With only two knobs for both pickups, I would think that this was to be a master volume and master tone. It could also work as two separate volumes, but I like the option of the tone control. For a tone, you will need a capacitor at a rating of .050mf up to .100mf

What rating are the pots? If any? 250K or 500K?
Are the pickups single coil split like a Precision bass, or split like a Les Paul Humbucker?

First of all, if you are in a big hurry, bypass all pots and wire the pickups (one or both) directly to the output jack. With two pickups, I would choose the neck pickup. (A P-Bass only has one pickup and it sounds awesome.)
As I am sure you know, the shield is the ground and the other wires are connected to the tip or positive terminal on the jack.

If you want to go ahead and wire this thing up all the way, lets start at the jack.

Jack: There are two posts, one that connects to the tip and the other is the ground or shield. The ground gets connected from the jack to the body of the volume pot. The ground is also connected to the body of the tone pot and shields from one or both pickups. as seen in this diagram, if it shows up. The ground is also attached to the underside of the bridge and the left post of the volume pot (as you are looking at it from the back of the pot.)

The positive or small wires are attached to the right post of the volume pot. and the center post of the volume pot is connected to the tip terminal on the output jack.

Your tone control is basically a loop to and from the volume pot. It's purpose is to simply bleed off the high frequencies to ground by running them through a capacitor. Connect the right volume post (the same on that connects the positive pickup wire) to the left terminal on the tone pot. The capacitor is connected between the center tone pot terminal and the volume pot ground. (Either the left terminal or the body. The other tone pot terminal is unused.

That should get you going if all your components are in working condition. Use the Stew Mac P-bass diagram and simply wire the neck pickup or both pickups the same way. It seems like there should be a switch.

One other thing I will mention. They don't show it on the diagram that a P-bass is sheilded underneath the pickguard with copper foil. This would connect the bodies of both pots to ground. You may have to also run a ground wire between both pot bodies.

Don't forget to ground the bridge, or you could have a nasty buzz.

I sure hope this helps, Jim.
Good luck and God Bless,
Michael T.

------------------
UTILITY MAN PRODUCTIONS
'73 EMMONS D10 FATBACK, '92 EMMONS D10 LASHLEY LEGRANDE,
'85 DOBRO 60DS, '95 DOBRO F60S,
'95 MELOBAR CUSTOM, 1955 FENDER TRIPLE NECK STRINGMASTER. EVANS, FENDER, PEAVEY,
and MESA BOOGIE Amps.

Jim Cohen · Post by **Jim Cohen** » 26 Apr 2003 5:10 am

Wow, Michael! Thank you sooo much for all this wonderful info; you really knocked yourself out on this one for me and I appreciate it. I'll have to muddle my way thru the rehearsal today but try to digest this stuff this afternoon and maybe be able to change it around in time for the performance tomorrow. Any chance you'll be home and I can phoneya? If so, email your phone # to me at jim@jimcohen.com
Thanks again!
jc

Michael T. Hermsmeyer · Post by **Michael T. Hermsmeyer** » 27 Apr 2003 9:01 pm

Sorry I wasn't available on the phone Jim.

How did it go? Were you able to get it going?

Michael T.

Gary Walker · Post by **Gary Walker** » 27 Apr 2003 9:52 pm

Hey Jimbeaux, I usually buy my basses already wired. If it says, "Some assembly required" I pass.

Jim Cohen · Post by **Jim Cohen** » 28 Apr 2003 5:36 am

Cute, Gary. Verrry cute... (Now go sit down)

Michael, no I didn't have enough time to get through it, so I just played the gig as is and will have to deal with it now. Fortunately, there's a loooong time between my bass 'gigs'! [This message was edited by Jim Cohen on 28 April 2003 at 06:36 AM.]

Jeremy Steele · Post by **Jeremy Steele** » 9 May 2003 4:13 am

Hey Michael, I used your instructions to change out the stock pickup on my P Bass to a Dimarzio. I'll add my thanks to Jim's for posting such good info. Do you have any tips on reducing noise? When I'm in "slapping" mode, I turn the high end way up, and if I take my hand off the strings there's an unpleasant buzzing. I've checked the grounding, and everything seems to be ok...is it possible that cheap pots might be the problem?