Passive PJ - Series/Parallel, reverse phase

[M-Bass-M]

I've got a passive PJ bass that I'm thinking of upgrading. The current set-up is a straight forward 3 knob vol/bal/tone.

To give me some interesting tonal options, I was thinking of the following:

- push/pull knob that reverses the phase on one of pickups;
- push/pull knob that changes between parallel to series wiring.

First off, has anybody attempted this before? I'd be interested to hear your thoughts.

Specifically, if was to do this then would I need both pickups to be humbuckers? As I understand it, if I wired a P and J in series, then the noisy J would remain noisy...which clearly I don't want!

Finally, would it be better to retain the vol/bal/tone configuration, or would it be better to go vol/vol/tone?

Cheers!

Mark

[hamfist]

Personally, I don't think you will achieve any extra musical tones with your suggestions, except perhaps putting all the pickups in series. Even then, I suspect you will get a big, boomy, rather muddy sound.
And yes if you have a std single coil J pickup it would introduce some 60Hz hum into the signal, but then it already does that whenever you are using at all, so what's the difference.

Of much more musical use IMO would be to add an East Parametric Mids control or something similar.

[pfretrock]

Tried that on my Squier Jaguar, which has 2 Js. (i'm a compulsive tinkerer) . Phase switch did nothing (that I could detect), Series dropped a lot of treble. OK if that's what you want but post #2 makes more sense. Two pups in series doubles the inductance that the signal has to pass through, which cuts treble.

[neepheid]

On any bass I've had with an out of phase option, I've found it to be the least useful thing ever on a bass, as (when it works) it sucks a lot of the bass and "oomph" out of the tone - what's left isn't very nice or useful IMO.

[M-Bass-M]

Thanks for all of the comments - glad I used BC to sense check my crazy ideas before actually going ahead with them!

Regarding the East mid control pot, I guess the main problem is that as I understand it I'd need to put a 9v battery somewhere...I'm currently completely passive.

[brensabre79]

I've tried both. Forget the Phase switch you'll just lose all the bass frequencies and be left with a honky mid heavy sound that is useful for absolutely nothing but sounding like a really awful guitar.

The series/parallel switch (or a 'Henry' switch as I call it) can be a useful mod. I have one on my Jazz - it makes it sound a bit like a Precision... boomy and less clarity with a slight volume boost.

As you already have a P pickup it may well be overkill!

Another mod I have is a Ricky style passive HPF on the bridge pickup. When activated this only lets the mid/treble from the bridge pickup through, so you always get the low frequency from the neck pickup (nice and fat), but you can add some mid/top to it from the BPU without any phase cancellation - so you don't get so much of the scooped sound of to pickups in parallel. Sounds a bit like a Rick.

Vol (push/pull Series/Parallel) • Stepped Blend switch (5 position rotary) • Tone (push/pull HPF)
Still with 3 knobs so completely reversible (as it's a 70s one).

The result is a Jazz bass, that can also sound passably like a Precision or Rick. Now if only it had a through neck...

Anyway, if any of the above appeals let me know and I'll try and dig out the diagrams

Edited November 20, 2014 by brensabre79

[pfretrock]

[quote name='brensabre79' timestamp='1416487576' post='2610700']
Another mod I have is a Ricky style passive HPF on the bridge pickup. When activated this only lets the mid/treble from the bridge pickup through, so you always get the low frequency from the neck pickup (nice and fat), but you can add some mid/top to it from the BPU without any phase cancellation - so you don't get so much of the scooped sound of to pickups in parallel. Sounds a bit like a Rick.

Vol (push/pull Series/Parallel) • Stepped Blend switch (5 position rotary) • Tone (push/pull HPF)
Still with 3 knobs so completely reversible (as it's a 70s one).

[/quote]

HPF definately worth trying for the cost of a cap and a switch. It works. One problem was I found the pull switch pots a bit noisy if used in the tone position. They are just not the same quality as the larger pots from well known makers.
Also they may be 6mm shaft, so 1/4 inch knobs (6.35mm) run off-centre. If the post are splined with a slot and the knobs are grub screw type, make sure the screw makes contact with the slot and not the spline. I think its more secure that way. Kept all my mods reversible also...

[brensabre79]

I think it depends which pots you get.
If you use the CTS ones they should be the same quality (this is what Fender use).
But yes they are generally only available in split shaft type.
Good tip on lining up the grub screw with the split btw - i found this one out the hard way!

[dincz]

I've only once had out of phase pickups and that was an accident. Tone is subjective but I can't imagine anyone finding this useful.