I was hoping someone could help me figue out what would be the best type of pots to use. I have a Fender Cowpoke (basically a P Bass Special) with ACTIVE P/J pickups and 2 concentric pots V/PJ blend and High Tone/Low Tone. I am replacing the electronics with passive pickups, SPB-3 Quarter Pounders for the P pickups and using the current J pickup that's in there. I only have spots for 2 pots (I don't want to drill any more holes) and I'd like to use the original concentric knobs (the active pots were long stems). Worse case scenario I can just wire up the P pickups and leave the J pickup disconnected as I play it on P most of the time. Is there a way to wire this with 2 pots so that I can use both the P/J pickups and volume and tone controls with concentric pots? From what I have read on other posts, I don't think I can set it up the same way as the knobs worked when the pickups were active. I hope I am not too confusing, thanks for any help!
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Help needed with pot selection for p/j with concentric knobs
- Thread starter strummer21
- Start date
You mentioned in your opening post that the bass had ACTIVE pickups. What are the values of the concentric pots presently in the bass? If they're only 100K or less then you might need to change them out for 250K or 500K concentric pots since you're switching to passive pickups.
P.S.: I tried looking on the Fender site for a schematic of a Fender Cowpoke or P-Bass Special to reference the pot values, but couldn't see an active one like your's here...
Invalid Link Removed
P.S.: I tried looking on the Fender site for a schematic of a Fender Cowpoke or P-Bass Special to reference the pot values, but couldn't see an active one like your's here...
Invalid Link Removed
Almost all active pickups have a low impedance output, which means that the pots are highly unlikely to be 250k or 500k.
New pots will probably be needed.
That's pretty much what I just finished saying.
No it's not. You questioned the value of the pots and said they might need to be swapped, I said they almost certainly will need to be swapped, regardless of the values, because it's unlikely that they would be appropriate for high impedance pickups.
You can do this, but I've found I use the tone knob mostly together with the P-pickup. So I'd go for either a stacked vol/tone for the p pickup and a vol for the jazz, or if you frequently dial the j in and out (as i do): a vol/vol for the pickups and a seperate tone.
More than likely the original pots won't do, and you'll need higher values. Is the tone cirquit seperate from the original pickups? because that might be left in place and you can keep the stacked tone knob. A v/v & high/low setup would do fine.
Also: the volume balance in a pj is tricky. The succes of combining a passive p and a active j depends very much on their volume. You might consider putting in a dedicated passive p/j set with a humcanceling j.
A tone on only one pickup will not work unless you isolate the pickups with either active buffering or a series resistance between the P's controls and the output.
Buffering will change the tone, and not allow the pickups' impedances to load against each other when placed in parallel.
Introducing a series resistance will reduce the output and darken up the signal.
- Aug 21, 2008
- 10,386
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- Owner, SGD Music Products
I say that's a good thing! Finally you can mix your pickups without the usual funkiness going on.
Wouldn't you need an RC circuit before the buffering to fake the cable impedance and "bring back" the passive tone? Or post-summing?
Thanks for all the responses. I am planning on using new pots, not trying to re-use the active pots. I am kind of a novice in wiring, but the best case scenario would be for me to have one master volume knob so I don't have to turn down 2 seperate knobs to silence the output. I'm sort of leaning towards just wiring it as a passive p bass and using long stem pots and keeping the original knobs and just leaving the jazz pickup in but not hooked up to anything. I wouldn't mind somehow being able to use the jazz pickup if it isn't too difficult to wire.
- Aug 21, 2008
- 10,386
- 252
- 68
- Disclosures
- Owner, SGD Music Products
Well it would allow you to finally hear both pickups, which is what a lot of PJ players complain about.
strummer21, if that's how you want it, maybe this is for you:
The Vol P is mislabeled, it actually acts as a master volume for all pickups. The Blend J lets you dial in how much of the J pickup you want in your sound. The Tone Master is just that, a regular tone control. You can use a stacked pot for either of those, I'd personally use a stacked for the Vol P (top deck) and Blend J (bottom deck) and have the tone on its own regular pot. Pot resistances and cap value to taste, I'm hoping someone will chime in with a good suggestion (500K/500K vol, 500K tone, .047uF cap?).
The Vol P is mislabeled, it actually acts as a master volume for all pickups. The Blend J lets you dial in how much of the J pickup you want in your sound. The Tone Master is just that, a regular tone control. You can use a stacked pot for either of those, I'd personally use a stacked for the Vol P (top deck) and Blend J (bottom deck) and have the tone on its own regular pot. Pot resistances and cap value to taste, I'm hoping someone will chime in with a good suggestion (500K/500K vol, 500K tone, .047uF cap?).
If the original Jazz pickup is active, and not being replaced, it cannot be used with the new passive P pickup, unless the P pickup is buffered. The lower output impedance of the J would load down the P.
Wow Stealth thanks for the whole schematic! That actually looks good, but as line6man said, i don't think my jazz pickup will have a high enough output to match the Quarter Pounder and I'm not going to buy another jazz pickup. I think I will just wire it as a P only and get new knobs. One last question, would leaving the jazz pickup in place and the wires coiled up but not connected to anything going to cause any noise or interference in any way?
No, I said the impedance would be too low, not that the output was too low. However, the J pickup could well have a lower output than the QP pickup. It's difficult to say until you try both pickups.
Concerning the unused J pickup, the P vs. PJ debaters tend to argue that the J pickup adds string pull. Personally, I would not be worried about this.
the stock cowpoke pickups are not themselves active, so there's no issue here. (they are cheap ceramic imports, so i would change them on principle, though).
as for "matching the output", the Js in P/Js never do anyway; the J just shapes the tone of the P, scooping mids and adding a pinch of highs. (i imagine active buffered pickup mixing would lose this effect.)
for an easy setup, how about just the P pickup with a volume and a tone, and have the tone be a push-pull that switches in the J as well when pulled out?
as for "matching the output", the Js in P/Js never do anyway; the J just shapes the tone of the P, scooping mids and adding a pinch of highs. (i imagine active buffered pickup mixing would lose this effect.)
for an easy setup, how about just the P pickup with a volume and a tone, and have the tone be a push-pull that switches in the J as well when pulled out?
