• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

Wiring Diagram for Jazz Parallel/Series Config

hey guys i just did the mod today and it sounds great except for one thing.

When i put the switch on there seems to be a little hum, when i touch any part of the metal on the bass it goes away, so i think this is a grounding issue but all my stuff is grounded. Maybe since there is more output the hum is louder, i don't know.


If you could help me out i'd be much obliged.
 
markjazzbassist said:
hey guys i just did the mod today and it sounds great except for one thing.

When i put the switch on there seems to be a little hum, when i touch any part of the metal on the bass it goes away, so i think this is a grounding issue but all my stuff is grounded. Maybe since there is more output the hum is louder, i don't know.


If you could help me out i'd be much obliged.

Did you do the shielding or just the series/parallel? If the latter, test for impedence between the switch case and other ground points. You may not have a good ground connection between the switch and the control plate, or a bad solder connection wherever the switch is grounded. Because in series the two pickups act like a big humbucker, so you should have no 60Hz hum.
 
Get a voltometer (also called a multimeter- you can get a digital one for $15-30 that will be fine for bass wiring jobs) and set it to the impedence mode. There are red (positive) and black (negative) leads coming from the meter. Place them against the two components you want to check for potential. In a circuit with good connections and no ground loops, you will read 0 ohms of potential between any two ground points. In a less than perfectly wired circuit you may get a few milliohms of potential- that means the ground isn't perfect and you may have ground loops that will result in audible noise through an amp. Or if a connection isn't there at all, you will read Infinite potential- that means something isn't soldered that needs to be.
 
Lyle Caldwell said:
Get a voltometer (also called a multimeter- you can get a digital one for $15-30 that will be fine for bass wiring jobs) and set it to the impedence mode. There are red (positive) and black (negative) leads coming from the meter. Place them against the two components you want to check for potential. In a circuit with good connections and no ground loops, you will read 0 ohms of potential between any two ground points. In a less than perfectly wired circuit you may get a few milliohms of potential- that means the ground isn't perfect and you may have ground loops that will result in audible noise through an amp. Or if a connection isn't there at all, you will read Infinite potential- that means something isn't soldered that needs to be.

All great information, and I don't want to sound like it is a complaint, but the multimeter mode is DC Resistance. You can call it Resistance, or Conductance (the lack of resistance), but unless you are looking at an AC signal it is not Impedance.

Also, set the meter to its lowest setting, usually something like 200 Ohms, and you will have the most sensitivity.
 
So you guys have me thinking (which is usually dangerous). But I was thinking of applying this mod to my OLP5. Because the pickup (I'm pretty sure) is basically two singe coils slapped together. With them being so closely spaced do you think that this would be an unwise chioce?
My thought is that this will be a VERY inexpensive mod that I can do to a very decent instrument. Would is be similar to the electronics of a Sterling?
BTW - Thanks. You guys are helping to make me a smarter people ;)
 
is there any way to get a push/pull switch with a center spot to have both pickups at the same time? I saw someone ask for about it, but I know nothing about schematics and just was wondering if I were to have someone do it for me (on a new bass - I'm getting a custom designed & built by a luthier) and was wondering how much it would add to the price, because I want 2 distinctively different pickups, and I'd like to be able to mix them and seperat them.


:( sorry if you feel I'm stupid and this already been asked, but the schematics here mean little to me sadly.
 

Latest posts