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Seymour Duncan STC-2S-BO troubleshooting

M

MxfmMod1k

Jan 1, 2019
31
11
25
Wisconsin
m.soundcloud.com
#1
I have a pj bass with a single volume and 3 way toggle. I wired the SD tone circuit and triple checked all the connections and their respective locations. When I played, there was normal volume, but the preamp did nothing no matter were the knobs were turned. I have an active/passive bypass switch wired in also. When the switch was set to passive (bypassing the preamp), the signal was killed.
I have the SPB-4 and STK-J1b wired to the 3 way toggle which then goes into the volume. From there, the signal goes through the dpdt switch and into the tone circuit. I can supply a wiring diagram as soon as i find in. It would be much appreciated is someone could lead me to any similar forums or advice and knowhow.
 
#3
This should work...
I had a different diagram up, but forgot to add the A/P switch...
7094551F-640D-4958-8806-1B1951B8DE21.jpeg
 
#4
eastcoasteddie said:
Here is a Jazz diagram for the BO preamp.
JazzBass_STCBO.pdf

The white wire for Preamp Input should connect to the pickup selector common terminal, the green output wire would go to the volume outer terminal and put the center to Tip.

your diagram would help to see what is in your bass.
Click to expand...
20191106_132459.jpg

I had a color coded version but have since lost it. Here's a quick recreation of it
 
#5
The only difference in my AP switch wiring and yours, is that in Passive, mine seems to ground the preamp input signal. I’m not sure if this has anything to do with what you’re experiencing.
But it sounds like an issue with the AP switch. Is it possible some connections are not being made inside? Check with an ohm-meter.

I have the same preamp, and wired as per my diagram’s AP switch. Not sure why, in Active, the tone controls wouldn’t work...

Now, my next question(s) may or may not sound rude or insulting...
But...
Is it possible that what you “believe” is Active or Passive, is opposite?
Is the battery good?
In Passive, tone controls wouldn’t work, but that is what you see in Active.
In Active, a dead battery would kill signal, exactly what you see in Passive...
Just a thought
 
Last edited:
#6
eastcoasteddie said:
The only difference in my AP switch wiring and yours, is that in Passive, mine seems to ground the preamp input signal. I’m not sure if this has anything to do with what you’re experiencing.
But it sounds like an issue with the AP switch. Is it possible some connections are not being made inside? Check with an ohm-meter.

I have the same preamp, and wired as per my diagram’s AP switch. Not sure why, in Active, the tone controls wouldn’t work...

Now, my next question(s) may or may not sound rude or insulting...
But...
Is it possible that what you “believe” is Active or Passive, is opposite?
Is the battery good?
In Passive, tone controls wouldn’t work, but that is what you see in Active.
In Active, a dead battery would kill signal, exactly what you see in Passive...
Just a thought
Click to expand...
So here's whats going down, it's really odd. To answer all your questions: The battery is unused, but I'm not sure for how long. When the AP switch is down (away from the jumper cable) there is volume but the knobs do nothing. When the AP switch is up (toward the jumper cable) the signal is killed. I switched out the switch for a new one twice and got the same results all three times. I dont have a passive tone control wired. Now that I'm thinking of it. It may be the battery. I had a spare in my case compartment in case my active Ibanez died mid-gig.
 
#7
eastcoasteddie said:
The only difference in my AP switch wiring and yours, is that in Passive, mine seems to ground the preamp input signal. I’m not sure if this has anything to do with what you’re experiencing.
But it sounds like an issue with the AP switch. Is it possible some connections are not being made inside? Check with an ohm-meter.

I have the same preamp, and wired as per my diagram’s AP switch. Not sure why, in Active, the tone controls wouldn’t work...

Now, my next question(s) may or may not sound rude or insulting...
But...
Is it possible that what you “believe” is Active or Passive, is opposite?
Is the battery good?
In Passive, tone controls wouldn’t work, but that is what you see in Active.
In Active, a dead battery would kill signal, exactly what you see in Passive...
Just a thought
Click to expand...
update: i changed the battery with one fresh out of the box. I made sure all the connections were nice and secure. Still the same problem. Now im officially out of ideas other than wiring the AP switch how you have it
 

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