4PDT Push Pull and new Hot Rod Sustainer guitar

[4real]

Me again...another incarnation of the sustainer, hopefully destined for some small scale commercial success is still in the works...

A lot of side projects have emerged from my work on this, and here's one that may well be of interest...a 4PDT Push-Pull Pot!

Here's the genesis...

The switching of the sustainer can get quite complicated...on the original prototype guitar, this was achieved with a 4PDT toggle switch. GN2 provided a scheme recently where I could use a super-switch (also a 4PDT) to achieve the necessary bypass and power switching for it...the sustainer would come on in one of the selector positions.

Now...I was bidding on eBay for S-1 fender switches (these are 4PDT), and for this guitar, I was actually trying to get a tele style with chrome knobs. The prices these things are going for are astronomical! Fender wont sell them as a separate part, and even if you are successful on a $50 part, you then have to bid on the knobs...possibly another $30....amazing, but there does seem to be quite a demand.

So...what to do. Obviously this kind of thing would be useful for a stock appearance and also opens up a vast array of possibilities for alternate pickup selections, as fender now offers. Not to mention, the application to the sustainer.

SO...I found a cheap supplier of push-pull pots from Hong Kong and bought a few. After taking one apart I was looking to see how one might be able to gang two of the switches together on a single pot, and it does seem to be possible...will be very soon making a couple...will let you know how that goes.

With this guitar then, I intend to have a stock strat, tele style knob layout with all three pot's push pull.

The first will be volume with a pull up operating the sustainer and doing all the bypassing of the selector, etc.

The second will be the drive control for the sustainer...pulling up will activate the harmonic function. A DPDT switch will do this job, but the pot will need to be 1k and so will need to be modified from another pot...exchanging the carbon strip if I can find a pot that matches.

The third will be a master tone, pulling up I intend to allow another whole range of tones from the selector...similar to the S-1 style of things.

The selector is a super-switch, so there are even more possibilities there!

The guitar is a humbucker bridge with two single coils. The SC's have been replaced with Fender Noiseless Jeff Beck models (so are humcanceling) and the HB is being replaced with a Seymour Duncan USA Jeff Beck model zebra...you see the theme.

A lot of hardware is being changed...locking tuners, roller trees, tremsetter... Plus there are some novel features including the intention to route a battery cavity in behind the trem block...removal of the battery can be done by pushing the trem all the way up (so the block moves forward) and slipping the battery out of a slot...well, that's the idea.

So...the question is, of all the circuits and pickup combinations, what would be the better ones for this type of guitar. Remember, the single coils are noiseless and the bridge pickup humbucking unless split...the pickups are relatively hot too.

There is a possibility of adding a small preamp on board and even a DIY piezo to be selected on the alternate pickup selection with the tone pot up at some future stage.

Anyway...is there a need for a 4PDT push-pull pot? Basically all they are are DPDT slider switches with a spring activated by an extended pot shaft. Having the pot shaft move two such switches looks quite doable...

thoughts?

pete

Check this one out that I was bidding on recently...

cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&rd=1&item=220157518347&ssPageName=STRK:MEWA:IT&ih=012

A$110 for a tele pots and 3 way selector with knobs...and this is not unusual...I think I may be onto something with a 4pdt push pull...

Have been working on this tonight and can do a fairly compact 4PDT...may even be able to do a 6PDT push/pull...no added depth to the assembly....but that would be a little tricky...don't know why you'd want one either.

Perhaps I should check out the S-1 selections from the fender site for a HB strat for ideas.

Also...have been dismantling the things and looks like I may be able to successfully change the carbon strip for different values (I need a 1k...the samples I have are 500k audio). Also, the ones I have got are actually adapted double gang shells, and although one wiper may have been removed, it may be possible to assemble it back into a dual gang push pull 2-4PDT switch pot!

If this is the cost of getting your hands on the slick S-1...then I think a push-pull is well worth considering...plus you can use the standard knobs...perhaps I will make a few and eBay them myself as faux S-1's...

[setain]

Hey Pete, what was the supplier you got the push-pull pots from? I've been looking for a source of cheap(er) push-pull pots for sometime.

Also, can you post pics of the dual-ganged push-pull pots when you make a couple?

[ashcatlt]

um, is there something special about these knobs you're looking at? Guitar Fetish sells 2 for 9.95.

[4real]

Yes...the pots on the S-1 switch have a centre portion that has a push-push 4pdt switch. You need the knob with a centre part that goes through the hollow pot spindle to activate the switch...

Here is the genuine alpha pot from the same site in a push-pull DPDT, so half the switching power. A 4pdt is like two of these ganged together.
store.guitarfetish.com/pudppo50auge.html

Ok...so I have bought stuff on ebay from this seller...
cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=300161213456&ssPageName=STRK:MEWA:IT&ih=020
The quality is not as good, but the price is half...these are the smaller pots and if you look carefully, it is actually a dual gang pot with the wiper removed from the lower portion and a switch attached below.

The switch is a basic slide affair but has a tiny clothes peg spring between it and another part that give the distinctive click between positions. When you take them apart, this spring jumps out and it is useless without it.

I have built one where I simply took a small dpdt slide switch, drilled a hole in the pot's switch side and screwed the two together so that when the pot's switch moves, so to does the slide...it works, but it is a little untidy.

I am now working on a new version where I take two slide dpdt switches and cut and glue these to the pot's actuator movement...the result is a lot neater and about the same size as the original switch but with twice the contacts.

This is taking a bit of work, but will post pics when finished. It is ideal for the project I am working on and if I can find a way to do it easily, I may well make a few.

I also explored taking these apart as I also want a 1k switch pot dpdt for the drive and harmonic function on this guitar. These are rare or non existance but if I swap the carbon strip from another pot, I can convert it and keep the same function. Again, it means dismantling the pot...so watch the spring!

As far as the strat wiring goes, I will install a standard switch pot on the tone and decide later if I wish to add other functions. My present idea is to have N,N+M,N+B,M+B,B on my super switch and take it from there.

Another intriguing possibility has come to mind...these noiseless pickups have a coil below the single coil pickups for noise canceling, it may be possible to switch in this noise canceling coil with the bridge pickup in split mode to keep the thing quiet. Perhaps such a coil split is an option for the tone knob.

What would be really cool, is a kind of switch trigger at the bottom of the pot...this could activate a push,push 4PDT kind of thing that I have found a cheap supply of. Would be tricky to make.

So far I am pretty pleased with the project guitar and as long as all goes well, it will be a bit of a stunner. I have found a whole heap of interesting hot-rod tweaks and cosmetic touches to include without it being cluttered or detracting from the sleek look of the thing.

pete