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Only half of the pickups work

jgbassking78

jgbassking78

Apr 2, 2011
18
5
#1
I am tinkerer, who recently has started to get very serious about learning the ins and outs of every bass I can get my hands on. Recently, I acquired a Tobias 6 string, which I felt had a great sound, but I am desiring to attempt to get it sounding more like late model MTD's as much as possible. As far as electronics go, I know this means the preamp and pickups should both be Bartolini.

I already had in my posession a stomp box mod, that contained a Bartolini preamp (pretty cool), but I started getting tired of the process it took just to set up and play. (Take out the bass, two cords, the pedal, change batteries in both, etc.)

Fast forward, I got the preamp out of the pedal and into the bass. Did my research and got all of the proper pots, new jack, etc. Researched and researched on how to properly wire everthing. Now im ready to plug up.

Low b sounds great
E sounds great
A sounds great
D sounds kinda weak
G sounds super weak
C is null and void

WTH? Can't figure this out and its annoying the hell outta me.

The one thing that is still stumping me it the fact that the stock soapbar pickups have 3 leads. A white, a ground, and a red lead. I've been hard pressed to find a diagram properly describing wiring a Bart pre with 3 wire pickups. I really don't know what to do with the red wires, and how to get the other half of both of these pickups to work. I'm really eager to get going on this bass. If anyone has any suggestions, please, they're all more than welcome.
 
#2
I have no idea about the pickups that come on that model, but I had an SX J pickup that showed the exact same symptoms. It turned out to be the magnet under the D-G strings had come unglued and attached itself to the E-A magnet. So my E-A strings sounded amazing and I had zero output from my D-G strings.
 
#3
That sounds very plausible. I guess the problem I would have, if that is the case, is that these are soapbar pickups that are sealed underneath. I have no "safe" idea as to how to access the magnets inside. What you described sounds exactly what im dealing with.
 
#4
How where those pickups originally wired? Do you know what model they are?

They sound like they are split coils, so one coil covers two strings, and the other covers three strings. You only have the one coil connected.

Have you connected the red to anything? Try connecting it to hot or ground and see what you get.
 
#6
jgbassking78 said:
They are the original pickups for the bass. Specifically what kind they are, im really not sure. The reds aren't currently connected to anything. I will try them to ground shortly.
Click to expand...

OK, but before you put in the new preamp, where the reds wired to anything?

Clearly you changed the wiring from the pickups when you did the install.

And also try them to hot.
 
#7
They were. They were grouped to one connection. The problem is the original preamp was a circuit board that did not have that particular post labeled, as well as most of the other connections. That basically caused me to have to figure most of it out by previous experience and guestimation. I have been a little busy today, but I plan to try it out before the night is out.
 
#8
So I didn't get to work on the bass tonight, but I did get to look back at the original circuit board. I looked at the solder side of the board, traced the lines. Turns out it is tied to the red lead from the battery, andis the first contact in the line. So that's promising. I'll try to get into it tomorrow. Thanks for your help guys. I'll keep you posted.
 
#9
SGD Lutherie said:
OK, but before you put in the new preamp, where the reds wired to anything?

Clearly you changed the wiring from the pickups when you did the install.

And also try them to hot.
Click to expand...

Hey David, once again you were spot on. I tried attaching them to ground first. I did get highs, but lost everything in active mode. As soon as I hooked it into the hot, the bass came alive. It sounds amazing. The thing that is confusing with this set up, is I'm using an 18v Bart pre, one batt has red connected to the pre, the other black. I realize now that'sto complete the loop. Also, this pre, as previously stated, was in a pedal form, and is missing a piece. All of that, including dealing with a three lead pup, just threw me for a loop. But I totally appreciate the help. Thanks.
 

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