1 Volume, 1 Tone HSS upgrade

TonyC63

I have a "teaching guitar" (£35 Pacifica) that I use to learn various guitar modding techniques on.

I was looking to have a hot HSS setup so I've bought and fitted a couple of Iron Gear Texas Loco single coils and a Dirty Torque Humbucker. Even with the stock pots and wiring they sound much better than the stock 112 pickups and it has a lot more crunch to it.

I have a 500k Push/ Pull Volume, 500k tone and CRL 5 way switch ordered but I was wondering in order to balance the single coils and humbuckers could you use a Stacked Concentric Audio Taper Pot - 250K/500K for the tone and wire it like two separate pots (like a regular two tone pot Strat. 250k side to single coils and 500k side to humbucker) and if this is possible what would the wiring layout look like?  In my ignorance I feel this wouldn't be difficult until you factor the coil split on the humbucker into the equation.

Any thoughts, wiring layout ideas and links to sites that might help me would be appreciated

ICBM

TonyC63 said:

I have a 500k Push/ Pull Volume, 500k tone and CRL 5 way switch ordered but I was wondering in order to balance the single coils and humbuckers could you use a Stacked Concentric Audio Taper Pot - 250K/500K for the tone and wire it like two separate pots (like a regular two tone pot Strat. 250k side to single coils and 500k side to humbucker) and if this is possible what would the wiring layout look like?  In my ignorance I feel this wouldn't be difficult until you factor the coil split on the humbucker into the equation.

This is more complicated and expensive than it needs to be and will make the switching needlessly complex and unreliable.

What to do is use 500K pots for both, and use the other side of the pickup selector switch and the second pole of the push-pull to engage a 500K resistor (470K is the nearest standard value) to emulate a 250K volume pot when the single-coil pickups are in use or the humbucker is split. It's the volume pot value that matters most, not the tone.

I would also use the push-pull for the tone pot not the volume unless you really prefer it in the front position - the tapers are often not as good.

I don't have the wiring diagram drawn out, but I think there's another thread here with it... or if you can follow a 'descriptive' schematic -

If you label the six terminals on the push-pull as

1  4
2  5
3  6

(1 and 4 closest to the pot body)

1 to ground
2 to the humbucker coil split connection
3 no connection
4 to the volume pot input (end) terminal
5 to the 470K resistor which then goes to ground at the other end
6 to the neck and middle pickup terminals on the second side of the selector switch

The two rotors on each side of the selector are connected together (as normal for Strat wiring where the second side selects the tone controls).

Does any of that make sense?

Funkfingers

What ICBM wrote.

Additionally, I am not certain that the control cavity in older Pacifica 112 guitars is deep enough to accommodate push/pull, push/push or stacked up dual concentric or dual ganged pots.

The more recent variant with rear-mounted controls might fair better in this respect.

Dave_Mc

What @ICBM said (and definitely worth checking it's deep enough for a push-pull as @Funkfingers said!)

If you're doing a partial split on the humbucker you might not need the resistor to simulate the 250k pot when it's split (as the partial split makes things a lot warmer/darker anyway). The Dirty Torque may be hot enough not to need a partial split resistor, though. But all of the humbuckers I've wired to split (admittedly not as hot as the Dirty Torque), I've just used a partial split resistor and not bothered with the switched 470k resistor as it's a lot easier to wire! 

TonyC63

@ICBM Brilliant stuff, well explained so even a Noob like me can understand things. I'll do a little more research around the switch connections but I'm pretty sure I understand what is being taught

@Funkfingers I'll have a measure up on the cavity when the pots arrive and get the power tools out if necessary.

@Dave_Mc Prior to your suggestion I didn't even know what a partial split was but if my research has informed me correctly I'll be coil splitting a 16.4kOhm humbucker to a 8.2kOhm single coil which is still hotter than my neck (6.2kOhm) and middle (6.5kOhm) SC's.

I do appreciate all your input. In a week or so we'll see whether I have understood things properly.

Dave_Mc

TonyC63 said:

@Dave_Mc Prior to your suggestion I didn't even know what a partial split was but if my research has informed me correctly I'll be coil splitting a 16.4kOhm humbucker to a 8.2kOhm single coil which is still hotter than my neck (6.2kOhm) and middle (6.5kOhm) SC's.

It may not be- that 16.4k humbucker is most likely wired with 44 AWG, and those single coils are most likely wired with 42AWG. Going up a wire gauge adds ~25% DC resistance for the same number of turns (i.e. same output). So that 8.2k would be more like 5.2k if it's 44AWG.

That's assuming that the humbucker is symmetrically-wound (it might not be or it might be; symmetrical means the same number of winds on each coil) and also assuming that single coils and split humbuckers are directly comparable in terms of output related to DC resistance (they're different enough in construction that they might not be- I'm not sure!).

All that being said, it's really a matter of personal preference etc.- you really won't know if you need a partial split resistor until you try it. I definitely felt that the JB in my Framus could have done with a partial split resistor even though it was similar output to yours (I never bothered because I was planning to swap it out eventually anyway). But other pickups are sometimes fine if they're hot and/or warm-sounding enough. You can also use a trimpot (probably 10k... 5k gives you more fine control, but you can run out of room especially on the bridge pickup where you might want slightly more than 5k!) which lets you really dial in the amount of partial split (if you don't lose the will to live before you've finished adjusting it!  ) but it's easier to adjust one of those in a rear-routed guitar... (I think some of the Pacificas are but some aren't)

normula1

I've often run a pair of wires under the edge of the pickguard and stuck the trimpot in a blob of blutack and then tweak away and then mount it properly once set.

Dave_Mc

normula1 said:

I've often run a pair of wires under the edge of the pickguard and stuck the trimpot in a blob of blutack and then tweak away and then mount it properly once set.

Yeah I thought of that but then I thought if it got moved when put under the scratchplate you'd have to take the whole thing off to adjust it again. Although to be fair, the trimpots I have don't seem to want to move without a fair bit of force, so maybe they've thought of that! And you can always take a multimeter reading once you've got it set how you want it, and then check it again periodically, both through a cable plugged into the guitar's input jack, just to check it hasn't moved appreciably (slightly variations are probably just indicative of a temperature change rather than the trimpot's being moved).

Also I should add @TonyC63 - I just remembered that Irongear helpfully does list its wire gauges for its pickups. The Dirty Torque is indeed 44AWG and the Texas Loco is 42AWG, so what I said about the relative resistances should (more or less) hold- though as I said, whether splits' resistances are directly relatable to genuine Strat single coil resistances, I'm not so sure.

TonyC63

Well it makes noise and the push pull tone pot splits the coil but I don't seem to have any tone control.  I think I have diagnosed the issue (no connection between the left lug of volume pot and centre lug of tone pot) and should know later today. I do appreciate the help  

TonyC63

Ok so I  love the new tones coming from the upgrade on the Pacifica but the tone control isn't having any effect.  I thought it was because I needed to hook up the CTS push pull tone pot output (middle lug) to the volume input lug but all I got was silence so I'm at a loss of what to do.  I'm 99.9% sure it's all wired as per @ICBM description but are the lugs meant to be connected and if so from what tone lug to what volume lug or switch lug?  My assumption is the sweeper / wiper lug needs connected somewhere or are the solder points on the CTS Push /Pull superceding these?  Cheers 

ICBM

The easiest way to wire it is usually to connect the input terminal of the volume pot to the anticlockwise end terminal of the tone pot - directly facing it if the pots are set with the terminals pointing at each other - and the tone control middle terminal to the tone cap, then the other end of the cap to ground. Neither tone pot terminal should be connected to anything else.

An alternative if the cap has long leads is to put the cap between the volume and tone pots - the same terminals - and ground the tone pot middle terminal.

TonyC63

Just like to say thanks everything is working as it should be now. My new favourite guitar