PJ VVT wiring with Pull Kill of Jazz Pickup?

[zacmac]

I wired up my PJ with standard VVT Jazz style wiring and like it but I would like to have the ability to do a pull pot to take the bridge pickup out of the circuit and get a standard P tone without the load from the bridge PU. Is this possible and if so can someone tell me how to wire the bridge pu thru the push/pull pot?

thanks in advance

 

[AMJBASS]

You probably could do that, but to be honest I don't see how its going to accomplish what you want. The problem(although its not really a big problem) with the PJ setup is the magnetic interaction between the 2 pickups and the strings. Taking out the Jazz pickup from the chain is not going to eliminate those 2 issues as the pickup is still going to be there. I've got a Fender MIA Deluxe PJ wired VVT(with EMG's GZR-PJ set) and its the best sounding bass I've owned in a long time. Rolling off the Jazz pickup gives you 95% of the sound of a straight Precision.

 

[line6man]

All you have to do is put a SPST switch between the output of the bridge pickup's volume pot, and the jack.

I'm not convinced that string pull is a factor in achieving P bass tone. I am also not convinced that removing a pot from the circuit is really worth doing. The difference is so subtle that it's just wasting time.

As a side note, just because you remove the bridge pickup's volume pot, does not mean that the control scheme will behave like a P bass. You will still have the wiper terminal of the neck pickup's volume pot wired as an input, rather than an output, and you will still have a tone control parallel to the jack rather than parallel to the pickup.

 

[RobbieK]

If you use bright strings and have a hi-fi sounding amp, you'll hear a slight difference in the treble (with the tone pot maxed) when you switch out the other pot. You can achieve more or less the same thing with a no-load tone pot.

OTOH, if you like to switch directly from one sound to the other mid song, then a switch as line6 has described is pretty cool. You can have the bridge pickup's vol up, and switch it in and out. I do sort of the same thing in my main gigging bass (a P/J) with a bypass switch on the blend pot. It allows me to switch straight from mostly P or mostly J, to both pickups full and unloaded by the blend pot. This works well as a slap switch.

 

[OrphicTrench]

Hey guys, sorry for bringing up this old thread. So the question would be: what would be the best wiring on a PJ bass in order to have a P-Bass tone? Is it possible to have a P-Bass tone with a PJ? If so, how?

 

[Killed_by_Death]

If you turn the volume of the bridge pickup fully counterclockwise you have a real Precision (split-coil) timbre.

With the caveat that you're using 500K Ohm pots.

If you're using 250K Ohm pots you'll have some loss of signal & treble.

 

[Jim C]

What if:
PJ bass
Passive pups only, an active blend pot is OK if needed

I want to be able to kill the J pup and eliminate loading on the P;
Never tried this with 500K pots but I can hear it with 250K.

I like the sound of these basses with 250K pots; what changes occur with 500K?

Now the problem
When is the mid position (both pups on) how can I either blend or use two volume pots so that I can vary the amount of signal from pup vs. the other?
A singal tone control is fine

 

[Killed_by_Death]

When you have a single split-coil pickup & one 250K Ohm pot, with the volume pot dimed you've got 250K Ohms between the signal & ground.
Now imagine you have a P/J with two 500K Ohm pots. One is dimed, one is fully counterclockwise.
This presents the same 250K Ohms between the signal & ground (two 500K Ohm pots in parallel = 250K Ohm).

 

[RobbieK]

Yeah, with the j turned all the way down, it's not the pickup that's effecting the P pickup, it's actually the extra pot. (In fact with a standard VVT wiring, the J will be shorted.) So I'd recommend desoldering the hot wire from the clockwise lug of the J vol pot, and putting in a temporary switch. Now turn the J all the way down, and audition the bass while switching the load of the pot in and out. The difference is extremely subtle, and only really noticeable if you like new strings and have a bright sounding rig. If you like flatwounds and old school jamerson thumping tone, you really won't hear a difference.

But if you can hear a difference then yeah, there's lots of ways to defeat one of the 250K loads on the P ppickup. Try a no-load tone pot. This way, with the tone control dimed, the remaining vol pots create the same load as the vol and tone pots do in a standard P. Or as KBD said replace the vols with a couple of 500K linear pots. Pretty much the same story. Or even replace the P vol with a no-load volume pot (my invention!). This way, when the P vol is dimed, the remaning J vol pot and tone pot again, leave the same load as the two pots in a standard P. You could also use a shorter cable with less capacitance. This will have sort of the same effect. You could also use a push-pull and have it wired as the test switch.

But yeah, try the temporary switch first.

 

[Jim C]

Thanks to you both; now I get it.
With using 500K pots, is the tone brighter with each individual pup, both together, or unchanged tone from using a P with a 250K pot?

 

[Killed_by_Death]

definitely brighter & with the added high frequencies, slightly more output

 

[bigtone23]

WalterW has a diagram for an ungrounded blend pot that works great. He takes it to the unloaded maximum by scratching away the trace so you fully and electronically disengage a pickup when the blend is at it's extremes. This is a way to get an isolated P pickup short of a 3 way pickup selector switch.

 

[RodRy]

...Or even replace the P vol with a no-load volume pot (my invention!)...

Hey Robbie,
I watched your vid of making a no-load volume pot, and I wondered if you would sell those? Etsy or something? My hands are just too full of other projects right now, but it seemed like it may be a good idea for my Tune P/J active to passive conversion.
Cheers!

 

[JimmyM]

You probably could do that, but to be honest I don't see how its going to accomplish what you want. The problem(although its not really a big problem) with the PJ setup is the magnetic interaction between the 2 pickups and the strings. Taking out the Jazz pickup from the chain is not going to eliminate those 2 issues as the pickup is still going to be there. I've got a Fender MIA Deluxe PJ wired VVT(with EMG's GZR-PJ set) and its the best sounding bass I've owned in a long time. Rolling off the Jazz pickup gives you 95% of the sound of a straight Precision.

I'd say 100%. I think this business about a J in the circuit making a P pickup sound different is a lot of hogwash, at least in most setups.

 

[Killed_by_Death]

TBH if you were using 250K pots all along you might not notice at all, because the timbre was already dulled down enough.

 

[JimmyM]

TBH if you were using 250K pots all along you might not notice at all, because the timbre was already dulled down enough.

Bah...I once did an experiment wiring my GZR P direct to the output jack vs using it in the VVT circuit with the GZR J. No difference in tone.

 

[Killed_by_Death]

That's because the GZR is already dulled down.

 

[JimmyM]

That's because the GZR is already dulled down.

Why don't you dull down?

 

[Killed_by_Death]

logic will prevail
I did the same thing, but with a Rickenbacker 4004.

The difference was amazing & TBH I should have left it wired directly to the jack, because the next day I wired it up correctly (VVT) & I missed the clanky, bright, grungy sound it had the night prior.

If you're wiring a pickup directly to the jack & cannot hear a difference, two things are possible:

A: that pickup never had any top-end to begin with
B: someone needs to have their ears cleaned (I'm serious, I had mine cleaned & the difference was appalling!)

However, I've heard the GZRs in your demo & I think it's the former.