Squier Jazz / T-40 frankenbuild

[pnut166]

Been kickin` this idea around for awhile now. Picked up a T-40 about a year ago, on advice from fellow TBers. Love love love ! the sound. Ergonomics and playability, er, not so much. So I picked this up yesterday on a CL steal. Gonna mod it and drop the T-40 electronics in it. I plan to try and keep the T-40 sound, so pickup spacing will remain identical as possible. Questions remaining: leave the bridge pup "naked" sans PG, or extend it back as with the T-40 ? Keep the Jazz control plate / PG layout, or go for a one-piece PG like the T-40 ? Any and all suggestions, tips, etc. appreciated. Anyone feel free to throw up any red flags with my plan ! Disassembly of both basses starts tomorrow; pics coming.

[pnut166]

T-40 layout [IMG][/IMG]

[ronaldpdbrandt]

With the addition of the extra knob and the switch to the control area, I think your going to need a bit more room than a Jazz control plate can handle. I mean, yeah, you could jam them all in, but it will probably look really awkward, and the knobs would be hard to turn.

If you go with leaving the bridge pickup "naked", you could do a Marcus Miller Jazz pickguard, which accommodates the extra control stuff:

[pnut166]

If I went with a plate, it`d be like the Deluxe, and move the jack to the body edge. Not sure where to put the two toggles. The MM - type is probably best, but I`d definitely make it flow better and more streamlined. Something akin to just lengthening the PG out to cover the plate area, extending back and curling up a little like a P, maybe ?

[TheEmptyCell]

I'd stick with standard J bass control plate and pickguard, don't mess with a bigger guard.

Personally, I'd ditch the phase switch altogether, then do VTVT, moving the jack t the body edge. If you want to stil, be able to select the bridge pickup coil when it's soloed and singled, put a push/pull for the bridge pickup volume. You need the stock tone pots to get the single/HB selection, I guess, but I don't now about volume controls. Just put the pickup switch on the pickguard. If you wanted to get nuts, you could use a Strat style 3, 4 or 5 way switch for all sorts of sounds (more than 3 could do series/parallel, in/out of phase, etc.)

[Stealth]

You don't need the stock tone pots to get the HB/SC switching. They're just creatively wired regular pots. And you can just as easily ditch the three-way switch if you want to keep it V/T V/T.

Here's how a regular T-40 is wired.
You can ignore switch S1 (phase switch for the bridge PU, treat as if it were connecting the top left and center left, top right and center right).
As for switch S2 (pickup selector), in order to skip it you need to get 2 extra parts - two small 220k resistors. Solder the wire from the bridge volume to one end of the first 220k resistor. Solder the wire from the neck volume to one end of the other 220k resistor. Then solder the free resistor legs together and add a third wire (it should form a T or Y of sorts) - that goes to the output jack.

The 220k resistors prevent the tone controls from interacting with any other components not "in their branch" - so the neck volume and tone will affect the neck pickup only, and vice versa.

[wraub]

I think it'd look better with no guard at all, but not sure of the body routing you have there.
If you go with a full pickguard, you have to deal with the offset J body, as well as the PU mounting rings (unless you rout the body accordingly and hang the PUs from the 'guard). However, the T40 'guard is oversize in a more pleasing way than the MM Jazz, imo. Cleaner and more evocative of the instrument's lines.
Just have that offset thing to deal with...

wraub

[Godfather]

I am doing the same exact thing !......except that I have an SX neck, it is the same concept......same body, same electronics.....
So, I am going to sit back and watch you before I proceed

Obviously, I am wishing you the best of luck .....and for unselfish purposes, of course

[pnut166]

Originally Posted by Stealth

You don't need the stock tone pots to get the HB/SC switching. They're just creatively wired regular pots. And you can just as easily ditch the three-way switch if you want to keep it V/T V/T.

Here's how a regular T-40 is wired.
You can ignore switch S1 (phase switch for the bridge PU, treat as if it were connecting the top left and center left, top right and center right).
As for switch S2 (pickup selector), in order to skip it you need to get 2 extra parts - two small 220k resistors. Solder the wire from the bridge volume to one end of the first 220k resistor. Solder the wire from the neck volume to one end of the other 220k resistor. Then solder the free resistor legs together and add a third wire (it should form a T or Y of sorts) - that goes to the output jack.

The 220k resistors prevent the tone controls from interacting with any other components not "in their branch" - so the neck volume and tone will affect the neck pickup only, and vice versa.

This is all interesting. I thought I had read before that there was something proprietary in the pots. According to the manual, the tone controls not only shape tone from #1-7, but #7-10 activate the single - coil mode. I`m not a wiring guru, but I kinda see what you`re saying, as far as how that`s achieved through regular pots. Hmmm... the plot thickens.

[Stealth]

Originally Posted by pnut166

This is all interesting. I thought I had read before that there was something proprietary in the pots. According to the manual, the tone controls not only shape tone from #1-7, but #7-10 activate the single - coil mode. I`m not a wiring guru, but I kinda see what you`re saying, as far as how that`s achieved through regular pots. Hmmm... the plot thickens.

The only proprietary thing about it is that Peavey thought about it first, or at least appears to be the first one to put it into production. Seymour Duncan calls this type of control "spin-a-split", but they'd only included it in their schematic in the past 2 years or so.

It all comes town to the fact his double-coil pickups have the end of the first coil and start of the second joined together into a single wire. That wire is a "tap" between the pickups, and the tone control then shifts how much of the second coil (the coil between the "tap" and the ground is still in the circuit). If you turn the tone down, the "tap" will be joined to the ground without any resistance in-between, and you'll have only the first coil active.

In fact, have a read of Hartley Peavey's The Ancient Order of the Mystic Magnetic Pickup. It's a fun read overall which explains quite a bit how pickups and electronics work (and why some standards in the industry are completely idiotic), but the explanation of the Peavey Tone control starts on page 13, in the right-hand column.

[pnut166]

So now the thought shifts to...what about a stacked-knob layout ? Two of the plate holes for the stacked knobs, two for the switches, and a heel jack ? I know the pup selector switch is kinda redundant, but I do like being able to go on / off with a switch flick. Doable ?

[TheEmptyCell]

Stacked knob is good. Get the little detent plates that go under them to hold the bottom knob more tightly in place so you don't tweak the bottom everytime you tweak the top.

Ditch the phase switch but absolutely keep the pickup switch. Like I said, you could even go crazy with a 4 or 5 way switch (rotary), and have series/parallel, phase switching... whatever!

[pnut166]

Well, I like the phase switch for a few tunes. The 5-way sounds cool, but the wiring scares me. I`m NOT up to snuff on wiring. I can solder, and I understand basic component functions...but when it comes to actually understanding a wiring layout, I`m pretty dense I got some black posterboards...gonna do some PG mock-ups this week and post pics.

[xaxxat]

Here's a T-40 Fury pickguard I mocked up. The bottom of the guard is a Fury, the top a T-40. The P pup was just for reference. I kept the original T-40 pup placement.

I think a naked bridge pup with a Marcus Miller type pickguard is the way to go with a Jazz body.

[pnut166]

Originally Posted by xaxxat

Here's a T-40 Fury pickguard I mocked up. The bottom of the guard is a Fury, the top a T-40. The P pup was just for reference. I kept the original T-40 pup placement.

I think a naked bridge pup with a Marcus Miller type pickguard is the way to go with a Jazz body.

I`ve seen this before - you did a good job ! Did you ever actually do this mod, or, like me, think about it for the last year ?

[Stealth]

I might find some time on Friday to crank out an easy-to-read wiring diagram for you. Just decide on what you wish it to do.

A vol/tone stack for each of the T-40 pickups is a cool idea, but if they're left resistorless, the spin-a-split tones will affect everything, if isolated with resistors, the output'll drop and won't be able to match the Precision's output. Maybe it'd be a good idea to go with the following?

• Volume, spin-a-split for each T-40 but without the tone capacitor
• Volume for the P, global tone

or

• Spin-a-split for each T-40 but without the tone capacitor
• T-40 blend
• Volume for the P, global tone

Or some other combination?

[xaxxat]

Originally Posted by pnut166

I`ve seen this before - you did a good job ! Did you ever actually do this mod, or, like me, think about it for the last year ?

I never did the mod. I need to make a better T-40 routing template and have been lazy about getting around to it. I'm probably going to do a double P mod on my Fury as I have a hot Dyna P pup that would be a nice bridge pup.

Check with me next year.

[pnut166]

Originally Posted by Stealth

I might find some time on Friday to crank out an easy-to-read wiring diagram for you. Just decide on what you wish it to do.

A vol/tone stack for each of the T-40 pickups is a cool idea, but if they're left resistorless, the spin-a-split tones will affect everything, if isolated with resistors, the output'll drop and won't be able to match the Precision's output. Maybe it'd be a good idea to go with the following?

• Volume, spin-a-split for each T-40 but without the tone capacitor
• Volume for the P, global tone

or

• Spin-a-split for each T-40 but without the tone capacitor
• T-40 blend
• Volume for the P, global tone

Or some other combination?

Okay, I`m a little confused (and maybe you are too ?) There is no P pup - just the T-40 electronics. Big thanks on the offer of helping a wiring dunce I`m leaning towards stacked knobs - one for each pup w / vol & tone. Keeping the two switches, and using the 4-hole Jazz plate, moving to a side jack. This may be an overly simplistic way of thinking about this, and I haven`t looked under the hood of the T-40 yet, but wouldn`t I simply have to unsolder at the lugs and resolder to the new pots, leaving everything else intact ? I`m not totally decided on the layout yet - the PG design is gonna be a big factor which way I go ultimately. Thanks to everybody for their insight !

[pnut166]

Originally Posted by xaxxat

Check with me next year.

Roger !

[pnut166]

I`m diggin` it Used the PG as a template, took the top edge up a tad. Had to bump the bridge pup back just a bit. Opinions ?