Pablos RC-4

Ended up going with white again. Should be here pretty soon.

Wiring question: So, after wiring this thing up I've noticed a couple of oddities. The centre position of the switch (both pickups) is noticeably quieter than either of the single pickups by themselves and when the volume of either is dropped (still in the centre position), even very slightly, it kills the signal from that pickup all together. Only get sound from both pickups when the volumes are equal. There is also a loud clack when using the switch.

Does this sound like a busted switch or have I stuffed something up (more likely)?

hey Pablo, thats a strange problem, so does the volume pot work ok when either the bridge only or neck only pup are selected ?
sounds like its not your pots but most likely is your switch if the soldered connections are ok and its earthed to the bridge ok. Have you got the hot tip on the output jack the correct way ?

I have a feeling it could potentially be a combination of things. Your pickups are a Fender bridge and Gretsch neck, right? It's possible there could be a phase issue when they're combined in the middle position which could impact the output level, or it could just be faulty contacts in the switch, or both. But I think there may be something more as well. Are you using the PBG RC4 wiring diagram, and are your pots 500K A or B? Maybe post some pics of your wiring setup?

I am using the same layout as that diagram and yes, Fender in the bridge and Gretch in the neck. Pots are all Bourns 500k audio taper. I was pretty thorough with my soldering and I've gone over it since and everything seems good. I hadn't even considered the phase issue, how would I check that?

Here's the only pic of the wiring I've got
http://i.imgur.com/tRYGYFy.jpg

Thanks Scott and Wokka.

your wiring appears to be ok Pablo, think Weirdy maybe onto something. will be a bugger if you have to match the pups !

Buy some more colours! Easiest way to test the phase issue (assuming at least one of the pups has separate positive, negative and ground/shield) is just reverse the positive and negative connections on that pup then give it a listen in the middle position. If you have a multimeter you can do some specific tests.

Edit: Just did a quick search, looks like Fender has red as hot and green as ground, while Gretsch probably has white as hot and black as ground... I think.

The layout is LP style with the pickups on the outer lug of the volume pot and the switch on the middle lug, so if you want Jazz bass style independent volumes you may want to swap the pickup (and tone link) to the middle lug and the switch on the outer lug. Not sure if that would help with the volume sensitivity issue.

I'd say phasing or the switch's connection/function would be the issue/s here. It's happened to me before in the past mixing pups.

Thanks heaps for the help guys, I really appreciate it. :)

It seems phasing is the best explanation for the weirdness. So after reading up a bit and watching that excellent video (thank you Scott), I have three ideas, all of which are probably going to demonstrate exactly how little I still understand. Only dealing with the Fender pickup as it's the easier of the two to move/modify. I'll start with the simplest.

1. Flip the pickup 180 degrees. To me this sounds too simple, but in my mind it does swap the magnets to where they need to go. Might not have enough slack on the wires.

2. Reverse the hot and ground wire. I keep coming across this solution, but invariably paired with folk who say it won't work.

3. Reverse the wiring on the pickup itself. Currently it's wired up like this
http://i.imgur.com/DjUYa8s.jpg
If I swapped it around to this configuration
http://i.imgur.com/9DzWtlG.jpg
will that do what I need it to?

Opinions? Will any of these work?

Thanks again, once again this forum proving invaluable.

hey Pablo, probably best wait for the guru Weirdy to answer that one.
In the meantime I'd try option 1 and flip it 180 degrees, doesn't have to be screwed down (hopefully the screw mount holes should line up). You may have to lengthen the wire but to me this seems the simplest possible solution without mucking around with the pickup wiring configuration

Flipping it may *slightly* change the tone of that pickup by itself, but it won't affect the phasing in relation to the other pickup. That's controlled by the configuration within the pickup itself, regardless of its physical orientation. Options 2 and 3 are essentially the same, it's just that option 3 is doing the reversing within the pickup itself.

What wires do you have coming out of each pickup, are they both two conductor like in the image above? If so, just reverse your hot and ground connections for the bridge pup and give that a try. If that does correct the phase issue, if that's what this is, the sound should be noticeably fatter in the middle position.

Aw crap, I never thought about the change in tone. Both pickups are two condutor, the only difference is the Gretsch has one lead with an inner and outer core. I am loving how the fender sounds right now, so I might flip hot/ground on the gretsch and see where that gets me as it's the weaker sounding of the two.

Cheers Scott.

sounds like the way to go Pablo, hopefully you can sort this out

Me too. Two days left to get it into GOTM. I reckon I can do it. New pickguard and truss cover are on, I'll try to get some pics together this arvo.

as if the GOTM judges don't have enough headaches already !

Reversing the hot and ground won't change the tone of an individual pickup, just how it interacts when combined with another pickup. The potential slight change in tone I was talking about was only from physically flipping the pickup 180 degrees (though it probably wouldn't be detectable), but as I said that wouldn't alter the phase of the pickup anyway.

Your bridge pup doesn't have a chrome casing so that would be the better option to reverse the hot and ground on. If you reverse the hot and ground on a pup with a chrome casing and that casing is linked to its ground (and it usually is if there's no separate shield wire) then the casing becomes part of your 'hot' and fingers can easily touch a casing when playing.

Once again, you are a freakin champion Scott! Another thing I would never have thought of. Bloody legend. You really are the wiring guru.

Pic dump
http://i.imgur.com/5hbnuT8.jpg
http://i.imgur.com/5yjstFo.jpg
http://i.imgur.com/guT2ZXW.jpg
http://i.imgur.com/st0y2i8.jpg
http://i.imgur.com/MN0f3Cy.jpg
http://i.imgur.com/N58U2kt.jpg
http://i.imgur.com/dTVrwLX.jpg
http://i.imgur.com/V1PXOa3.jpg
Ok, I'm sticking a fork in this one. There's still a few small issues with the wiring (probably going to tear it all out and start again) but otherwise done. I am tremendously satisfied with how it's turned out. Plays great, sounds great, looks great (I think anyway). Thanks heaps for everyone's help, couldn't have done it without you all. :)







Coming soon......
http://img41.imageshack.us/img41/7303/20090807119.jpg

Pablo nicely finished. Never been a Ricky fan and i ignore em when i see them in shops, but the colour and look of that bass keeps dragging me back into your build diary. love it.

Stunning job Pablo!

turned out very nicely Pablo, so your next project going to be a JM-1 modified ?

Thanks guys.

@Wokka, my first scratchie mate. Well, half scratch, buying the neck.

nice one Pablo, sounds awesome. It's such a sexy shape. Not sure how the tremelo system works on the picture you posted, different to the JM-1 has a similar to a strat tremelo

I'm gonna hardtail it. I don't really like trems.

cool less routing too !
what timber you got in mind Pabs ?

Got some lovely slabs of pine. Enough for two guitars. Or, more likely, enough to recover from a stuff up.

Looks amazing Pabs - just freakin amazing. Love this bass to death. Great job!

cheers,
Gav.

Thanks Gav, I'm really enjoying it so far. Will get a demo up as soon as I can record one without sucking massively. So, maybe never lol.

Did you get the middle position issue sorted?

I think so. I reversed the fender pickup and that seemed to equalize the volumes. The other issues are still there, so I'll probably have to do a full rewire down the track. For now, it works well enough.

good stuff Pabs, pine is easy and soft to work with and cheap to replace.
Glad the volume issues have been resolved. Look forward to a sound demo