Another coil tap question...

[Jem]

I've finally got my (undamaged!) SL3 but the volume pot is a little bit dodgy - it gets stiff when I try turning the volume up between 10 & 11

So I was thinking of replacing it, then I thought perhaps it would be cool to replace it with a push / volume pot to coil tap all of the 3 PuPs. Is this possible with a single switch or would it require too many poles to work?

If it's possible, has anyone got any source for wiring diagrams for doing this? I'm handy enough with a soldering iron but would prefer to reduce the head scratching trying to get this mod done...

[charvel750]

Not sure what you meant by volume between "10 and 11" as all of my pots go to 20!

Well, you can certainly replace it with a push/pull volume pot to tap all of the 3 pickups. To wire it that way, notice the upper set of lugs on the pot. The highest two should be left alone. The middle two should be connected to each other, and that is where you will wire the pickups' "coil tap" wires. The lowest two should be connected to eachother and that goes to the ground. Wire the lower set of lugs as normal like the existing pot. Try it out, let us know.

[delt]

^ um, wouldn't he be shorting the signals from the pickups together if he does that?

[Jem]

Heh ok I'll make sure the replacement goes up to 20 as well

I've ordered a replacement pot, that wiring makes perfect sense, I just have to work out which colours are which on the PuPs and it should be a gift. My only slight concern now is whether the cavity space is going to be deep enough for the replacement pot, I assume it's all standard and there will be no problems but I can't find any dimensional information, nor could I get a reply from AllParts when I mailed them to ask yesterday.

Fingers crossed all will be good...

[Jem]

delt - oerrrr ummm will I? I thought that at the moment 1 side of the coil-pairs goes to ground so the switch effectively pulls half the coils to ground and leaves only the 2nd half so that sounded logical to me.

However, I hear what you're saying... connecting together those middle wires may not be a good idea. Argh! Just after I order the push/pull pot!

Can anyone give me a 2nd opinion here? Nothing's gonna blow up if I try it but I'd like to get it right first time

[charvel750]

You know, I'm just a dumbass mf'er, so you can ignore anything I say, hell, what the fuck do I know, I'm just a dumbass, I haven't been around. Look, I just wired a pair of push pulls in a Les Paul, maybe what I said isn't clear, but that's how to do it. You can't blow up anything. But just ignore my useless advice so I don't have to give it out anymore

[Jem]

Jeeeeeez calm down Havin' a bad day?

I appreciate your advice , I can see what you're saying and trusted it enough to go and buy the damn pot. But I can also see what delt is saying as the coils become wired together when running with the split turned off. But perhaps this doesn't matter for some reason I don't understand BUT WOULD LIKE TO LEARN.

You just wired a PAIR of push/pulls in an LP - so I'm guessing you didn't connect together the coils from each PuP but wired each to its own switch so that wouldn't show the problem delt picked up on. If you've done 3 PUPs to 1 switch and it works, that's cool, that's all I need to know.

[charvel750]

Jeeeeeez calm down Havin' a bad day?

I appreciate your advice , I can see what you're saying and trusted it enough to go and buy the damn pot. But I can also see what delt is saying as the coils become wired together when running with the split turned off. But perhaps this doesn't matter for some reason I don't understand BUT WOULD LIKE TO LEARN.

You just wired a PAIR of push/pulls in an LP - so I'm guessing you didn't connect together the coils from each PuP but wired each to its own switch so that wouldn't show the problem delt picked up on. If you've done 3 PUPs to 1 switch and it works, that's cool, that's all I need to know.

I'm calm, no problems. If you run all the pickups' "coil tap" wires to the middle lugs of the push/pull you will get it to work. I have done that wiring before, and I explained how to do it, so there's really no need to solicit additional opinions (note that no one else replied here) and act as though my advice is meaningless. If I hadn't replied, where would this thread be?

[MountainDog]

Once you've been here for a while, you'll learn that Charvel750 has a lot of knowledge. As he mentioned, no other 'elder' JCFers added to his reply.

You mentioned you'd like to learn....OK:
- 4 wire pickups have one wire going to 'hot' (usually first going to the pickup selector, one wire (plus a 'bare-wire' ground sometimes) going to ground, with the other two wires soldered together to join the coils (so both coils are working). Remember This: one wire to 'hot' (switch) other wire to ground (the same ground all the other pickups are wired to).
- when you connect the 'coil-tap' wires to the switch as described above, then engaging the switch means you 'short-to-ground' those wires. By doing so, you bypass one of the coils. Your 'hot' wire is still going to the switch, but now the ground path is the new path via the switch...therefore you still have one wire of each pickup to the 'hot' and the other to ground (the same ground as the other pickups).

So there isn't any 'shorting of signals' by doing this, the signals from each pickup are still controlled by the position of the pickup selector switch. Each pickup shared the same ground originally, and they share the same ground again when the coil tap is engaged, all you are doing is eliminating one coil of each pickup from the electrical path.

[Jem]

I'm sorry if it appeared to you that I didn't appreciate your advice charvel750, I do appreciate responses, that's the point of the place isn't it? As I've already said, if I thought it was meaningless I'd hardly have gone and bought the part to do it, would I?

So delt made me think about this some more, and I'm sorry if the feeling round here is that only 800+ posts makes him a noob who knows nothing but if no-one else replies on a thread that can mean EITHER no-one else knows jack about guitar electronics OR everyone agrees with you. My psychic abilities aren't the best these days... if I ignored his posting then he could accuse me of saying his posts are meaningless as well... jeez I can't win!

Not having been around jcf for long just means I haven't been here long, period. I wired up a couple of my guitars way back in the day but hey in 20 years memory does get a bit fuzzy so I ask questions.

I did some more reading up on circuits since posting and understand what you & MountainDog have said. I also found circuits on www.guitarelectronics.com and some Jap dude at www.geocities.jp/dgb_studio/faq.htm who has some more info and in neither of these locations could I find any examples where the coil-taps on separate pups were ever shorted together so it got me thinking and this is the point I'm stuck on if you don't mind enlightening me...

Taking this as 2 different wirings (i.e. coil-tap, and all-coils):

In coil-tap mode:
I see perfectly how taking the coil-tap wires to ground switches off one set of the coils, and how the selector switch works as before with no modifications. I have no problem whatsoever with that.

In all-coils mode:
In this position all (6) coil-tap wires are shorted together on the switch (unless I am misunderstanding what you are saying or you're intending me to have a three-pole switch and I haven't found one of them). So this means that if I select just the bridge HB then I am also getting the first coil of each of the other HBs in the signal path. This surely cannot be good? I fail to see how they can possible NOT be in the signal path as they are all connected together at the switch.

Excuse the shitty drawing, but here's what I'm thinking is going to happen (orange boxes for coils in the signal path, white boxes for those out of the signal path, selector switch not shown but assumed to be on the lowest PuP in both cases):



Maybe I'm mis-understanding this but it seems to me that without a 3-pole switch, all the PuP coil taps interfere with each other and create paths to ground through some part of all of the PuPs when not tapped.

I would really love to know where my obvious error is, because I just can't see it at present no matter how much I stare at it