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Double p with Vol/blend/tone is really quiet

A

arav87

Supporting Member
Dec 23, 2008
79
115
Philadelphia, Pa
www.myspace.com
#1
I have followed this diagram, only difference is a concentric 250/250k pot for vol/tone instead of individual, and they're p bass pickups instead of j's. Anyway, it is very quiet compared to my regular p bass.

Is this the nature of blend pots? Is it because p bass pickups are dual coil so it's getting funky because of some series or parallel thing?

Any ideas on improving this diagram for my use case?

Thanks!


1784102454897.jpeg
 
#3
On a double-P (I have 2) it's also possible to swap the coils and end up with them electrically in-phase, but magnetically out of phase.

The simple way to determine if that's the case is to use a small magnet and try to touch each side of each pickup.
One side should attract your magnet and the other side should repel it.

Check that both EA coils and both DG coils behave the same - i.e. if the neck pickup EA attracts the magnet, the bridge pickup EA also needs to attract it.
 
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#4
groovaholic said:
On a double-P (I have 2) it's also possible to swap the coils and end up with them electrically in-phase, but magnetically out of phase.

The simple way to determine if that's the case is to use a small magnet and try to touch each side of each pickup.
One side should attract your magnet and the other side should repel it.

Check that both EA coils and both DG coils behave the same - i.e. if the neck pickup EA attracts the magnet, the bridge pickup EA also needs to attract it.
Click to expand...
Interesting. Good note!
 
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#8
groovaholic said:
On a double-P (I have 2) it's also possible to swap the coils and end up with them electrically in-phase, but magnetically out of phase.

The simple way to determine if that's the case is to use a small magnet and try to touch each side of each pickup.
One side should attract your magnet and the other side should repel it.

Check that both EA coils and both DG coils behave the same - i.e. if the neck pickup EA attracts the magnet, the bridge pickup EA also needs to attract it.
Click to expand...
They're both loller p bass pickups that were got new, so I think they're wired the same and properly. Bridge is overwound to compensate for bridge pickup stuff.
 
#9
may be a PITA but you could try wiring one at a time to the volume knob to see if the output is "normal".
this would help to isolate the issue to the blend function of the stacked knob or to a pickup

also, seeing as how you are not really following this drawing, are you sure the concentric pot is wired correctly?

fwiw, i use a vol/blend/tone configuration on my jazz bass and it does not seem quiet. also have the same on my Ibanez BTBs thought those have active pre-amps. in any case, none of my basses seem quiet due to the balance knob.

good luck
kgb
 
#10
with a dual P you have to be aware of the magnetic polarity of each coil, the e/a coils and then the d/g coils have to have opposite north/south polarity. take any kind of cheap magnet and for both of the e/a coils it should stick to one and repel the other. keeping in mind using the same color code for your 4 or 2 cond wiring it should work, on my BCR i verified this having similar problems to you and the bass opened up completely.

i think. if i am wrong please explain why as this did work for me
IMG_9606.jpeg
 
#12
I would start by disconnecting the pan pot from the volume pot and then connecting one pickup to the volume pot to see if volume returns to normal.

Also, I would be more inclined to use the 'no-load ungrounded' M/N blend wiring which has the advantage of truly isolating each pickup at the ends of the rotation.

walterw

Thread 'Ultimate No-load Ungrounded Blend Pot (Pics!)'

after talking about the "ungrounded blend" thing for a while now, i finally got around to snapping some pics of one while i was installing it!

this is a 250k M/N pot that i've also modded to be "no-load" by cutting traces, so that at each extreme the "off" pickup is entirely disconnected. (i figured out that even with no parallel ground load path, at the ends of the travel each pickup was still being loaded by the other pickup's path to ground, so the 250kΩ of the pot plus the 8kΩ or whatever of the "off" pickup.)

instead, with the traces cut this pot really is just like a...
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