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New (to me) bolin electronics/pickups problem...

Chace90

Supporting Member
Feb 1, 2002
1,813
1,307
Denver, CO
I apologize for this post being so long!

I just got this bass last week Took it straight to my luthier for a check and setup. Played a rehearsal and it sounded fine. It's got active EMG-TM double coil pickups and 5 piezos, one on each string saddle. Active EMG preamp with bass, treble, mid & mid shift knobs. 18V

Took it to a gig the same night, and it didn't work! The piezo's worked fine, but are unusable in my opinion. The amp was getting a signal from the EMG's, but it was incredibly weak. Tried changing the batteries to no avail. I was reduced to opening the control cavity to check for a loose or shorting connection. Couldn't find any, so I closed it back up. To my surprise, it was working again! No idea why, but didn't think much of it. I set her down for a while before we went on. Came back on stage to test it, wasn't working again!

Here's my best description, based on what happened today. I was practicing and it was having the same problem except now it was affecting all three pickups (EMGs & piezos). I'd be left with barely any signal and a lot of noise and hiss. For some reason, when I plucked harder, I could get more sound and it would keep getting louder and louder. However, it was still ridden with hiss and noise. At first I thought the volume pot for the EMG's might not be working right because I could turn it a few times and it would work again. My work around has been to turn up the piezos full (separate volume knob, much higher gain) and pluck hard until the electronics would kick back in, and then turn the piezos off again.

It's as if pushing the electronics hard enough when their acting up makes the system work normally. Are piezos dependent on batteries? Does anyone have any clue what's going on here, because I have no idea. My luthier suggested perhaps changing the circuit. He also thought it could possibly be that the EMG's were both giving out (highly unlikely), but that doesn't seem to be the case now because the piezos are exhibiting the same problem.

Anyone ever have this problem or something similar happen before?
 
are the batteries separated/snug/not touching anything in the cavity? and as for the emg pre, how are the piezos connected in the circuit? is this a bolin setup, or "after market" (emg)? :hmm:

Batteries are connected and not touching anything they shouldn't be in the cavity (as far as I can tell). Not positive, but I believe the piezos are last in the chain of pickups, meaning last connected to the output. This is the stock Bolin setup, no aftermarket (again, as far as I know). The website would not suggest otherwise.
 
Batteries are connected and not touching anything they shouldn't be in the cavity (as far as I can tell). Not positive, but I believe the piezos are last in the chain of pickups, meaning last connected to the output. This is the stock Bolin setup, no aftermarket (again, as far as I know). The website would not suggest otherwise.

Are the batteries in a flip top box where there are no battery snap connectors, or do they have snap on connectors on wires?
 
Flip top, no actual connectors. Just points where they need to meet.

Are you totally sure that the batteries are really connecting? I've known a similar to yours where they weren't.

The vibration, from working the bass hard, caused the batteries to connect momentarily here and there, and the signal came back for short a while, and then would go away again.

Just a thought?
 
Are you totally sure that the batteries are really connecting? I've known a similar to yours where they weren't.

The vibration, from working the bass hard, caused the batteries to connect momentarily here and there, and the signal came back for short a while, and then would go away again.

Just a thought?

I'll definitely look into it. I hope it's something simple like that, because I can't afford to change out any electronics right now! :)
 
So, I think my problem yesterday with the entire system was in fact the batteries coming loose. The original problem still persists though. And I think I've figured that out too.

It seems to be the volume pot for the EMGs. The piezos work perfectly right now, regardless of the EMGs functionality. I think there's either a short in the knob or its wiring, or the pot is just going bad. It scratches when I turn it. If it hit the strings hard enough, the EMGs fall out. But when I push the volume knob to it's max, it comes back. Very weird.
 

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