Series/SC-inside/Parallel/SC-outside/ indi-pup control--whew!

Here's my attempt at the holy grail.

This mod starts with DavePlayBass's (DPB) Series/SC-inside/Parallel, but makes a few changes. First, it eliminates the pup-selector switch. This is replaced with a stacked, concentric volume pot. No need to switch pups on or off. Just roll the vol up, down or off for each pup individually or together.

DPB's mod replaces the stock 2-way 4PDT switch with a 3-way 4PDT switch. This mod replaces the the 2-way 4PDT switch with with two 3-way DPDT switches. One goes where the pup selector switch used to be. This one works like the top half of DPB's switch and controls the neck pup. The 2nd goes where the old S/P switch was. This one works like the bottom half of DPB's switch and controls the bridge pup.

Other than that, I have tried to be faithful to DPB's diagram.

There are a couple of other items however that are worth mentioning. I had to change the tone circuit path because of the additional volume control. Stock wiring goes from the pup selector switch to treble pot to bass pot to volume. My mod requires the the volume pots to come first, since they replace the pup selector switch. So, this is wired...

V/V-->T-->B

My mod also replaces the stock Bass pot with a push-pull pot. With the pups in parallel, and the push-pull in the "up" position, this adds an SC-outside setting.

Two other itty bitty changes to stock...

There's a cap on the stock vol pot. I eliminated that.

I added a resistor between the tone circuit and the pre-amp.

The reason for those two changes have been discussed elsewhere...

So, now that I have drawn it, and gone through it several times with a pencil, I thought I'd post it (a) to see if anybody finds something wrong with it and (b) for use by anyone else who'd like to try it.



Couple of conventions to note... I don't have a great drawing program, so solder-posts are denoted by a black dot. All solder connections are at a black dot, except for connections that are grounded to pot housings, which are denoted by a green dot with a "down" arrow.

Caps are orange footballs with the value noted.

Resistors are pink circles with the values noted.

All wiring colors are as close to stock as I could keep them...with one exception. used a blue (rather than white) wire between the state-selector switches and the volume pots. There are no blue wires in original G&L wiring. This was just to avoid confusing the white wire from the pups with the "out" wire to the tone circuit.

OK, if anyone finds an error, I'll correct it and put up a new diagram--thanks in advance to anyone who does.

If no one does, hope this is helpful to somebody ;-)

This owes a huge debt to the meticulous wiring diagrams created by Ken Baker, and DPB's mod documents. Also to Ken, Dave, Jim and all the others who have patiently answered my questions in other threads.

 

Good question! Won't know until I actually do it. Wanted to get it diagrammed before doing it...and vetted by the experts such as yourself. You think your brain hurts! ;-)

 

Dude! I just realized that I did not credit you above... You were the first person I encountered who had used a stacked vol controls. AND the first person I encountered whose mods control both pups independently. Without your posts I would never have figured out how to get all four "states" and independent pup states without drilling new holes. Thanks for chiming in!

Reverse log taper? The one meg pot on this page is the one I got:

http://www.guitarpartsresource.com/electrical_pushpullpots.htm

It says it's a 1 meg audio taper with a solid shaft. I guess that means I may end up with the problem you mention. Rats!

I just wrote to the guys at Alpha Products since they seem to make most of the push-pull pots that people use. I asked if they make a 1 meg reverse log taper pot...or if one can be ordered.

If not, is there a work-around? Can resistors be added or something?

Do you use both settings?

Did that--I am pretty sure it was at your suggestion that I got a stacked CTS 500K/500K concentric pot. Probably should have noted it on the diagram....

I figure it'll be nice to have the options, even if you don't use them much--especially given how difficult it is to try out the settings in a real-world sort of way ahead of time.

 

Good suggestions!

Will update the graphic at some point. I have put the switch in the diagram exactly the way it orients, viewed from the bottom.

For now, though, thinking of the "0" as posts on the bottom of the switch...

0-0 0
0-0 0 switch toward bridge = Parallel

0-0 0
0 0-0 switch in middle = SC inside

0 0-0
0 0-0 switch toward neck = series

Mine's not shielded well so I plan do do that when everything is out of there.

Stock wiring is a birdsnest, and not really improved by my diagram, which seems to cause headaches (so it's not just me afterall ;-)

I tried to do what you suggested, but it's still confusing...basically I just left it the way it is done "stock." Jack ground to the treb pot housing. Treb pot housing to the vol pot housing and the bass pot housing. Bass pot housing to the bridge. In my diagram all grounds (except for the battery!) should connect to one of the three green dots...and from the treb pot to the jack.

Part of the confusion is that in stock wiring, sometimes grounds are green and sometimes they are black...and then there is the fact that one of the black wires coming off the bass pot is not a ground... I think this could be simplified, but I just tried to stay as close to stock as possible.

BTW, I did one more mod which is not on here...actually the only one that is done at this time. I put in a battery box. This makes it easy to pop the battery completely out for when I don't want to use it--which, like Sunbeast, is most of the time for me.

 

I don't cut the bass much...but your posts have made me think...and order a couple of parts. I found some CTS pots that have STSP push-pull switches. I ordered a couple of those, and I ordered a bass pot from G&L. I don't know if it's possible to switch out the wafers, but it'll cost me less than $20 to try. If I use two STSP switches (say, on the treb and the bass pots), I might get individual control for the outside SC mod... May not work, but I'll report back in any case.

 

Did a bit of research...and if there is a reverse log taper 1 meg pot with a push pull switch out there, I have not found it!

Given the chart above, the easiest way to do the mod would be to put an audio taper 250K push pull pot in the treb spot, instead of putting a push-pull on the bass slot. I can only find split shaft, but that's no biggie. Call that option #1.

Aahh! But there are other options, if I can do the wafer swap... Assuming I can do that, I could...

...make a concentric pot for both tone controls. All the pots would remain CTS and the proper values. Where the bass pot is I could put a three position DPDT swtich (like all the other). This would give me what a two position switch gives, plus the option of putting the neck pup in outside-SC, while leaving the bridge pickup with parallel/SC-inside/serial options. Call that option #2.

...Or, I can "make" two CTS pots with the proper values that have STSP push pull switches. This would allow me to put each pup in "normal" or "outside SC" mode individually. The only downside to this is that switch "up" would be "normal" mode and switch "down" would be "SC-outside" mode. That's fine, but a bit counter-intuitive. A tad easier to get confused in the heat of battle. Call this option #3.

Assuming all options are possible...which would you do?

Please feel free to comment if you think I'm going off the deep end ;-)

 

I think I will try the latter. I have a spare concentric pot, and have a proper 1 meg pot on order from GL... Have been curious about doing the wafer-switch.

I toyed with the idea of just doing the inside coil setting...perhaps that would be enough... I as about to just do the push-pull pot as you suggested... but today I was cruising by my favorite electronic parts store and found a 4 position, three pole, rotary switch...which is about the size of a normal CTS pot. With that I think I will have Indide, outside, series and parallel settings for each pup individually AND the controls will look the same from the front, except there will be two concentric pots. I should be able to operate the rotary switch with the the standard G&L chrome knob.