Wiring question: Jazz Bass V/B/T + Series/Parallel

[David Jayne]

I hate to seem like a troll, but I've done all of this stuff on passive J's and P/J's and it just never works right. Spent years messing around with this. You'll notice nobody sells a Jazz with V/B/T configuration unless it's active? Nobody. There are good reasons.
Again, don't mean to 'pee in your Cheerios' but there are problems with this that even the Big Guys won't touch.

 

[David Jayne]

95% of all tone pots are audio pots ...
4% might be linear pots, built in in old European and Asian basses from the 1960s and early 1970s.

Some confusion comes by the fact that pot declaration (printings) may vary form country / continent to country / continent ...

Hey, Hi there from Connecticut! Germany is my favorite non-USA country. LOVE Germany.

 

[michaelandrew]

Thanks for the replies.

My thought was to get a couple of after-market control panels and experiment with a few different configurations - pot values, tapers, series/parallel. I have two Bourns MN taper blend pots - 250 and 500 KOhms.

Any idea which after-market control panels fit the Squier best? Fender perhaps?

I might even go active; a while ago I put an Audere pre in a Yamaha RBX-765 and loved the result. Audere makes drop-in pre-amps for Jazz bases as well, so that's a posibility.

I'm guessing that the "Big Guys" avoid the V/B/T set-up to save money or because V/V/T is "traditional" on jazz basses; MN taper balance pots were developed for pro- and home stereo use and weren't always as readily available as they are now. Anyway, that's my theory and I'm sticking to it - for now (never been to Germany, never eat Cheerios).

 

[Cadfael]

Hi,

you can get a lot of cheap after-market control plates which fit to Fender and Squier Jazz Basses. In Germany I would say Rockinger/Göldo. In the USA Mighty Might an AllParts?

Even most cheaper control plates fit - and a JB control plate can even be fixed with one screw for experiments ...

OFF TOPIC: Germany is as different as the USA ...
I come from the German/Dutch border (where Eisenhower and Churchill first met on German ground during WWII). This is as similar to Berlin, Bavaria or the Black Forrest as Connecticut is similar to Florida, California or Alaska ...
I now have to live in Dortmund (only 80 miles away) but I have to translate some words. There's a different between the "right side" of the River Rhine (which is the left side to me) and the right side ...

 

[michaelandrew]

Cadfael - Actually I was in Germany once - to change planes in Frankfurt on my way to Vienna. I'm sure there are more interesting places in Germany than Flughafen Frankfurt. Cheers from Canada.

 

[MothBox]

Just finished wiring this up including the volume lug switch in #12 but I have a small issue. The volume knob seems to work anticlockwise for louder which I think is due to the lug switch. This is fine, but the blend knob seems to be a bit strange and I'm wondering if I'm shorting somewhere.

The 12 o'çlock of blend gives the neck PU only, fully clockwise both, anticlockwise gives neither! (in parallel PU).

Checked my wiring and it all seems fine - all connectors were checked on wiring and it looks like the schematic. Is it likely a shorting somewhere?

Pretty pleased it worked at all given how poor my soldering is!

 

[michaelandrew]

The volume knob seems to work anticlockwise for louder...

If you want clockwise of louder, try reversing the outer two connections on the volume pot - leave the centre connection as is.

The 12 o'çlock of blend gives the neck PU only, fully clockwise both, anticlockwise gives neither! (in parallel PU).

I can't think of a short that would cause this, but it could be a wiring error on the blend pot. It's important that the 4 outer lugs on the blend pot are "cross-wired" - that is, pin 1 on one goes to pin 3 on the other and vice-versa (pin 2 is the centre pin for both). If that's clear as mud, have another look at the diagram from Stealth.

Here's my suggestion - the ground is optional - I leave it out:

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Hope this helps.

 

[MothBox]

Thanks. Opened it up today to see on of the earth bonds on the tone pot had come off so ive fixed that up, made no difference.

The blend pot ive fully disconnected. I find it easier to totally rewire than fix up. Ive tested the pot itself and not entirely sure its working correctly.

The lower 3 lugs dont seem to respond when the knob is turned. The top three go from (if you number them 1 2 3 from left to right) knob full turned anticlockwise, 1 and 2 communicate; knob in centre, 2 and 3 only communicate; fully clockwise 2 and 3 only.

If the cross wiring connects up lugs 4 and 6 then that brings the bottom row into play but still dismisses lug 5. And i thought in centre position lugs 1,2,3 should all communicate?

Not sure if the pots burnt out as ive never tested one before.

 

[MothBox]

As the bottom deck isnt working im going to wire 4 and 5 together to have the bridge always connected. I rarely solo the neck PU so as a temp fix while i wait for a new blend pot it will have to do.

 

[michaelandrew]

What type of blend pot are you using?

If it's an MN taper blend pot, then you should see:

Centre (detent) position: Both pick-ups on full

R1 Resistance across pins 2 and 3 = 0 Ohms
R2 Resistance across pins 1 and 2 = 0 Ohms
​

Full clockwise - Neck pick-up on full:

R1 Resistance across pins 2 and 3 = 0 Ohms
R2 Resistance across pins 1 and 2 = Maximum​

Full anticlockwise - Bridge pick-up on full:

R1 Resistance across pins 2 and 3 = Maximum
R2 Resistance across pins 1 and 2 = 0 Ohms​

 

[MothBox]

What type of blend pot are you using?

The only marking is "WD500" on the side which I have taken to mean its 500k.

I've ordered a 250k and 500k to replace it. I think the bottom deck is broken, either due to the heat from soldering (if possible as I thought it was mechanical) or its just faulty.

Regardless of position none of the lower lugs communicate. This temp fix of wiring 4 & 5 together basically puts the bridge direct to output which is fine. It allows me to bring the neck in and out which is the only combination I use anyway.

Once the new blend arrives I'll crack open the old one to see if there is any indication of whats wrong.

 

[michaelandrew]

WD500 might be the house brand for WD Music (UK). I've had good luck with Bourns blend pots - haven't used any others.