P/J wiring... stupid questions

[wateroftyne]

Hi all

I've decided to add a J pickup to my fretless P, but rather than hack the body up (it's old), I've snagged a P body which is pre-routed for a P and a J.

As it's already routed, it got me wondering - how hard can this be? Can someone like me who can kind-of hold a soldering iron swap the electrics across and wire in a J, or is it rocket science?

Also... I like having two knobs on my bass. Can I bin the tone, and have vol/vol or vol/blend instead?

I realise getting matched pickups is another thing entirely, but I have a few bits lying around I can try first before I ring Mr. Wizard pickups.

Am I setting myself up for a bass that buzzes, and does odd things when both pups are maxxed? I know the Tony Franklin P has some sort of buffer in the J pickup.. do I need to get involved in that?

Cheers, all!

[bnt]

At a basic level, 2-pickup wiring is not hard. There are plenty of diagrams around, with the two main options being Fender Jazz style (2 volume controls) or Volume + Blend. Seymour Duncan has [url="http://www.seymourduncan.com/support/wiring-diagrams/"]plenty of diagrams[/url], including both those options, and a specific P/J diagram that is easy to follow.

IMHO the big issue will be pickup selection. The P-type pickup is humbucking by itself, but a standard Jazz pickup is not. With standard Fender Jazz wiring, the two pickups together form a humbucking pair, when both are turned up, but you won't have that option. If I was in your position I would be looking at a humbucking J-type for the rear slot, such as the (Seymour Duncan again) Jazz Stack (e.g the [url="http://www.seymourduncan.com/products/basslines/cutting-edge-1/stkj1_classic_f/"]Classic[/url] or [url="http://www.seymourduncan.com/products/basslines/cutting-edge-1/stkj2_hot_for_j/"]Hot[/url]). Or something similar, with 4-conductor wiring for more tone options.

Re Knobs, you could look at a Stacked knob for volume/blend, too avoid more drilling. You're totally free to drop the tone control altogether, as long as you never need it.

Edited October 10, 2008 by bnt

[wateroftyne]

Cheers. bnt!

[Dr.Dave]

Well I was having kittens until I read past the first few words of your post!

You go on to talk about experimenting before you contact Wizard , maybe that's the wrong way round. I found them very affable folks to talk to and think using their advice as a start point could prove more valuable - partic re pup balance.

I like Bnt's stack knob suggestion too.

[obbm]

[quote name='bnt' post='303733' date='Oct 10 2008, 11:47 AM']Re Knobs, you could look at a Stacked knob for volume/blend, too avoid more drilling. You're totally free to drop the tone control altogether, as long as you never need it.[/quote]

I think you will have great difficulty finding a stacked log + ganged log/antilog with centre detent for vol/blend.

[wateroftyne]

[quote name='Dr.Dave' post='304171' date='Oct 10 2008, 08:56 PM']Well I was having kittens until I read past the first few words of your post!

You go on to talk about experimenting before you contact Wizard , maybe that's the wrong way round. I found them very affable folks to talk to and think using their advice as a start point could prove more valuable - partic re pup balance.

I like Bnt's stack knob suggestion too.[/quote]

In an ideal world, you'd be right!

Unfortunately, the phrase of the day for this project is 'Cashflow? What Cashflow?' so I'm doing it as cheaply as possible... if I have a pickup lying around that'll do the trick, then that'll do me!

If not... I'll pick the phone up.

[The Burpster]

Wiring is pish easy if you go v/v/t which is what I'd recommned - look on SD's webby for simple wiring diags...


Oh and off to teh techie section....

[Thunderhead]

[quote name='obbm' post='304182' date='Oct 10 2008, 09:12 PM']I think you will have great difficulty finding a stacked log + ganged log/antilog with centre detent for vol/blend.[/quote]I would say impossible without custom ordering it from a pot manufacturer.

But there is another way - you can use a standard dual-concentric linear, with the pickups wired in series - that way you only need one pot for the blend. It works fine - I had a blend pot like that on my last bass, and actually a linear pot is OK for a volume as well.

To connect it, you wire the pickups in series (ground of pickup 1 grounded, hot of pickup 1 to ground of pickup 2, hot of pickup 2 to volume pot, while keeping any separate shields grounded), then connect the blend pot in parallel with the volume pot except that the middle tag is connected to the junction of the two pickups instead of the output jack.

The volume taper is pretty good, since the voltage sum of the two pickups is always equivalent to either pickup alone, no matter where the knob is set (assuming they have roughly equal outputs), and doesn't have the slight drop that you get in the middle of a normal log/antilog blend pot. The both-pickups sound is somewhat different from parallel blending though, it's a little darker and more midrangy.

However, if you're not bothered about a tone control the simplest by far is just to go for two volumes wired exactly like a Jazz. This also has the least compromised volume and tone when both are full up.

Edited October 12, 2008 by Thunderhead

[danlea]

Perhaps I'll chuck [url="http://basschat.co.uk/index.php?showtopic=25375"]this[/url] into the mix. Probably not exactly what you want, but maybe it'll be helpful in some respect.

[Mr. Foxen]

Other option, if you sometimes use tone all the way down is to have a push/pull to turn tone all the way off. I added a j pup to my p bass, but put it in the neck position, balanced about right there, but the hum thing was annoying.

[~tl]

If you're missing the tone control out, I like to add a treble bleed off capacitor/resistor combination. Even when the tone control is turned fully up, some of the treble is bled off through the cap and the full resistance of the tone pot. You can substitute this with a ~250kΩ fixed resistor and the normal sized capacitor (~.05µF) wired in series between the output and ground. Without it, the instrument will be pretty trebly, which may be what you're after. But if you're looking for an "authentic" tone then I'd recommend adding it. If you want more options you could add a switch or a push/pull pot to switch the bleed off or even to change the value of the resistor which will alter the tonal properties. Check out danlea's schematic (in the thread that he linked to a couple of posts up) for a fairly good implementation of this – it doesn't offer full bypass of the treble bleed, but has equivalents of the tone control being fully up, partially up and fully down.

Edited October 13, 2008 by ~tl