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EMG 40DC + BQC Very low output

John Bitner

John Bitner

Dec 4, 2021
10
8
#1
Help! Installed BQC in a bass that already had EMG40DC pups. The install was smooth since all connections are solderless except for the input jack. Checked power connections with a meter. Getting 18v at the circuit. Double checked all solderless connections. All are all the way on their pin. Double checked the EMG supplied diagram and the wiring is correct.
To even hear the output I need to keep the amp input at about 75% and master vol at like 75%. 800watt mesa head. My cabs should be melting the room. The amp is fine. Checked with another bass.
 
#3
About 7mm.

PXL_20221106_134140765.jpg
 
#5
Bypass the BQC (as you say, easy with the solderless connectors) and test the pickups separately. If they’re good, double-check each and every hot/ground connection to/from the BQC.
 
#6
Double checked all connections. Unplugged and reseated all of them. The input jack is not solderless. I've pulled the wires from it cleaned it up and resoldered just to be sure the solder was good. Pickups checked out yesterday. The same EMG pickups that came with this bass. 40DC. The change was adding the BQC pre. Can't make sense of this. Could I have a bad pre?
 
Last edited:
#9
John Bitner said:
Double checked all connections. Unplugged and reseated all of them. The input jack is not solderless. I've pulled the wires from it cleaned it up and resoldered just to be sure the solder was good. Pickups checked out yesterday. The same EMG pickups that came with this bass. 40DC. The change was adding the BQC pre. Can't make sense of this. Could I have a bad pre?
Click to expand...

Sorry if this is insultingly obvious, but checking absolutely everything is necessary- you have battery voltage connected to the BQC and the pickups both?

Assuming the answer is “yes”, then I’m out of ideas. You might have a bad BQC. Have you contacted EMG? Their customer service is pretty good.
 
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#12
John Bitner said:
About 7mm.

View attachment 4865090
Click to expand...
I know you said the change was the preamp but that distance still looks a bit far. EMGs don't work like other pickups. You're supposed to raise them as close to the strings as you can without them touching the strings as you play. Mine were installed by fretting the last fret and plucking the strings while raising the pickups until they touch. Then back them down a touch. Might help.
 
#13
I tried moving the pickups within a few mm of the strings. Ridiculously close. I ended up moving them back to the stock position where they were when I bought the bass. Since these pickups were already installed and at the height I'm showing in the picture, I'm assuming that they should still work even with a different preamp.
 
#15
lokikallas said:
Is it possible that the two pickups are wired in opposite polarity? Does one pickup soloed have the same issue with gain?
Click to expand...

John Bitner said:
Basically the same output from both or either using the balance.
Click to expand...

You may have missed the point of JB’s post. He asked if you checked that the polarity to the pickups is correct. If they are reversed then they will cancel each other out and will barely produce volume. Also, polarity may not effect balance depending upon the design.
 
#19
I have two basses equipped with two 40 J's and the whole BQC system. Really surprising how much lower in output these basses were, compared to my P-bass with a single EMG and just a volume and tone. The P bass kicks butt.. and the tone was killer on the builds with the whole system with 18V, but total output was weak.
My easy solution, was to install an EMG PA-2. I set the gain to match most of my other basses, and just put it in the cavity. Now, problem solved. But I have no idea why the output was lacking.
 

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