Bass signal decreases significantly after center detent on bass pot...?

MattS

MattS

Jan 17, 2011
267
111
4,571
Cheshire, CT
#1
I have an Ibanez SR505 bass and the Bass pot is a B100k pot with a center detent/midpoint. For some reason, the whole signal, overall volume, lowers significantly after the detent/midpoint turning clockwise. Anyone know what could be causing that? It didn't always do that. Not sure if the pot needs to be replaced OR if it's something with the pre-amp. Any help would be greatly appreciated. Thank you!
 
#4
This bass is eating batteries quicker than normal too, No it doesn't stay plugged in. I highly doubt that the pickups are out of phase, electronics have not been touched or modified as far as i know. Still looking for the culprit. What might cause the battery to die quicker?
Thank you all!
 
#5
MattS said:
This bass is eating batteries quicker than normal too, No it doesn't stay plugged in. I highly doubt that the pickups are out of phase, electronics have not been touched or modified as far as i know. Still looking for the culprit. What might cause the battery to die quicker?
Thank you all!
Click to expand...

A constantly draining battery is a sign of improper wiring. The jack needs to be wired to turn the circuit on and off. If it is wired to "on" at all times, the battery never stops draining.
 
#6
Go over to Ibanez's website and print out a copy of the wiring diagram for your bass. Ibanez publishes them for all their guiars and basses. Then carefully check every wire starting with the three on the output jack and make sure everything is the same as in the diagram. Odds are good the jack is just wired incorrectly. If it's not - and all your other connections are also wired correctly, then there's probably something wrong with either the jack (easy to replace) or the preamp itself.

There might be a short somewhere and your battery is being grounded even though nothing is plugged in. If it is shorting, the battery and/or some part of the wiring should feel warm or even hot to the touch. A 9V puts out decent current for a battery. If it's shorting you'll be able to feel it.
 
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#7
Your preamp ground is shorted to ring or if the pickups are active the ground on that is shorted to ring constantly powering it when it is unplugged.

Use a continuity meter or continuity setting on an ohm meter and find your active electronics grounding from the pickups and the preamp, test from ground on preamp to ring on the input jack without the cable plugged in. Do the same for the pickups if they are active. If you hear the tone you need to do some rewiring and attach thay preamp/ pickup ground to shield.

Also the pot could be bad, sometimes drop in level could be the pot having bad tracking capability.
 
#8
So i used my multimeter, continuity setting so it makes a beep. No cable in input jack. I did hear a beep when I touched the black wires of the preamp circuit (ground) to the ring of input jack (longer lug on left of input jack shown in diagram)... Is that NOT supposed to beep at all when cable is NOT in the input? If Yes, could it be a bad input jack and that is causing the draining battery, therefore best to start with a new input jack?
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