P/J bass series with isolated treble cut

Will_White

Will_White

Jul 1, 2011
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Salem, OR
#1
#3
With parallel wiring it is not possible to have isolated tone controls. With series wiring it is. WalterW recently described that here on TB but apparently is it well known elsewhere too. Yes, you can do it with a precision pickup. You wire one side of the tone circuit to the hot lead, the other side of the tone circuit to the ground lead, and you leave the wire that connects the two halves of the pickup unconnected to the tone control.
 
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#5
khutch said:
With parallel wiring it is not possible to have isolated tone controls. With series wiring it is. WalterW recently described that here on TB but apparently is it well known elsewhere too. Yes, you can do it with a precision pickup. You wire one side of the tone circuit to the hot lead, the other side of the tone circuit to the ground lead, and you leave the wire that connects the two halves of the pickup unconnected to the tone control.
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That's what I was hoping to hear, now I just have to buy 4 switches
 
#7
Jay2U said:
With a capacitor across the wires of the P-pup you'll cut off highs from that pup. As the J-pup is in series, it might gain a bit on the highs. The value of the capacitor should be determined by experimenting.
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Yep, that's what I'm going for, I prefer the highs of the bridge J but the lows are lacking thus the high cut on the P to get the rumbling lows, I'm going to wire it series/P pickup/ Parallel with a two position treble cut on the P in series, and a two position bass cut on the J in parallel for those Ric-ish tones, in parallel the treble cut will effect everything and in series the bass cut will effect everything.
 
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#8
20151130_121838.jpg

How does that diagram look? The P is the lower one and the J is on the top
 
#10
line6man said:
I'm not sure what you are trying to do, but whatever it is, that wiring is way off.
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I probably should of put labels on the switches, L>R it's treble cut for P (series) on/on/on with two caps, Bass cut switch for J (parallel) on/on/on with two caps , Series/P/Parallel on/on/on, kill switch (i realize that's not the best way but I have the switch on hand (i also just saw that the switch doesn't have a ground I'll have to fix that)). With that information, is it still Off?
 
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#11
Will_White said:
I probably should of put labels on the switches, L>R it's treble cut for P (series) on/on/on with two caps, Bass cut switch for J (parallel) on/on/on with two caps , Series/P/Parallel on/on/on, kill switch (i realize that's not the best way but I have the switch on hand). With that information, is it still Off?
Click to expand...

What you have is as follows:

Treble cut switch:
Up: One capacitor
Middle: Both capacitors in series
Down: Bypass

Bass cut switch:
Up: One capacitor
Middle: The other capacitor
Down: No sound

Series/parallel switch:
Up: Parallel out of phase
Middle: P pickup
Down: Series out of phase

Killswitch:
Up: "On"
Down: "On"
 
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#12
line6man said:
What you have is as follows:

Treble cut switch:
Up: One capacitor
Middle: Both capacitors in series
Down: Bypass

Bass cut switch:
Up: One capacitor
Middle: The other capacitor
Down: No sound

Series/parallel switch:
Up: Parallel out of phase
Middle: P pickup
Down: Series out of phase

Killswitch:
Up: "On"
Down: "On"
Click to expand...
Thanks for catching my mistakes, I think the treble cut is actually good going by this:
Diagram3b_WEB.jpg

The bass cut I left off the jumper, and I shouldn't of second guessed my self on the pickup polarity (thats what the little tick is above the top pickup), and I already noticed the groundless kill switch.
 
#13
well I guess it's possible when the pickups are in series with one another. (and fwiw there are ways to get some isolation when the pickups are in parallel too). but really, the point is, with two pickups blended in any way, can you really tell which treble its which?
 
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#14
RobbieK said:
well I guess it's possible when the pickups are in series with one another. (and fwiw there are ways to get some isolation when the pickups are in parallel too). but really, the point is, with two pickups blended in any way, can you really tell which treble its which?
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You can on a rick (with a bass cut on the bridge pickup), with standard "full signal" blends I don't think so (although soloed it's very different), but that's why I'm trying this approach, to get the treble of a solo bridge J with the added bottom of a P pickup in the "sweet spot"
 
#15
A few years ago I wired a jazz bass for a customer with two tone pots and a blend. I used a couple of resistors to isolate the tone pots (not as fender did, but as I have outlined on this board in the past) because she wanted to do as you said; roll the tonefrom one but not the other. with the blend in the middle, it was pretty much impossible to tell by ear whetherthe neck treble or the bridge treble was being cut.

where the isolation came into its own was when you wanted to quickly tweak the blend during a song without having to also tweak the tone. the owner was disappointed at first, but found herself rolling the treble from the bridge pickup and leaving the neck pickup's tone all the way up (btw they were no-load tone pots if memory serves). this way the blend sort of became a mid control in reverse.
 
#16
RobbieK said:
A few years ago I wired a jazz bass for a customer with two tone pots and a blend. I used a couple of resistors to isolate the tone pots (not as fender did, but as I have outlined on this board in the past) because she wanted to do as you said; roll the tonefrom one but not the other. with the blend in the middle, it was pretty much impossible to tell by ear whetherthe neck treble or the bridge treble was being cut.

where the isolation came into its own was when you wanted to quickly tweak the blend during a song without having to also tweak the tone. the owner was disappointed at first, but found herself rolling the treble from the bridge pickup and leaving the neck pickup's tone all the way up (btw they were no-load tone pots if memory serves). this way the blend sort of became a mid control in reverse.
Click to expand...
I think part of the "problem" with isolated tones in a parallel wiring scheme is that the signals don't sum like they do with parallel, so you don't get the treble on top of the bass of two pickups in series, you just get the treble from one and the bass from both of them mixed so with two nearly identical pickups there's not much tonal variation and you still get the phase cancellations of two pickups, with tonally different pickups (like a P and a J) I think the difference would be more noticeable but still not all that much in a parallel scheme. What makes the RIC bass cut different (some one can correct me if I'm wrong on this) is that the bass cut puts it slightly out of phase, and removes some of the frequencies that phase cancellation happen at so you get a more uniform less scooped response, with the added sparkle of the treble pickup.
 
#17
yeah that's a good point. I hadn't thought of that. the most obvious/audible (lowest) frequency that's cancelled is usually in that octave from 500-1000hz, depending on the pickup placement of course, and I guess more obvious the further apart the pickups are. And a passive tone control will roll off those frequencies and above...

I would still recommend trying a treble cut on both pickups. it would be goodto experiment and see which treble cut works better in this respect.

the other problem with blending series pickups is that you'll find the blend to be quite a bit louder than the solo'd pickups. there are ways around this though...
 
#18
After doing stuff like this on my instruments for the past 30yrs I came to the following conclusion: Keep it simple and don't try to re-invent the wheel.
My advice: Wire your bass like every PJ is supposed to be wired. If you don't like the sound change the pickups. Then if you try a few pickups and it stills sounds bad it means you got a lemon.

Keep in mind that those type of experimental wirings have been tried a million times since Leo created the first Fenders and the reason why no one stuck to it is: It does not work.

Pickups work well in series ONLY when they have been conceived to work in serie in first place. It often gets too muddy. Remember the S1 switch on the Jazz Basses? I did that way before Fender released their S1 and came to the same conclusion as everyone else who tried this mod, including Fender: it sucks.
 
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#19
RobbieK said:
the other problem with blending series pickups is that you'll find the blend to be quite a bit louder than the solo'd pickups. there are ways around this though...
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You say that like it's a bad thing ;) right now I use that as a passive boost going from solo P to to P/J in series, I don't use the J solo that much (thus the series, P, parallel with no solo J option)
, I will probably include an outboard solution to the volume bump though for when I want the tone without the boost.
Frenchy-Lefty said:
After doing stuff like this on my instruments for the past 30yrs I came to the following conclusion: Keep it simple and don't try to re-invent the wheel.
My advice: Wire your bass like every PJ is supposed to be wired. If you don't like the sound change the pickups. Then if you try a few pickups and it stills sounds bad it means you got a lemon.

Keep in mind that those type of experimental wirings have been tried a million times since Leo created the first Fenders and the reason why no one stuck to it is: It does not work.

Pickups work well in series ONLY when they have been conceived to work in serie in first place. It often gets too muddy. Remember the S1 switch on the Jazz Basses? I did that way before Fender released their S1 and came to the same conclusion as everyone else who tried this mod, including Fender: it sucks.
Click to expand...
Well I've been doing it wrong for the past year then and two volumes and a tone knob is simpler then a selector switch and a kill switch, thanks I had no idea.
 
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