SE Hollowbody Piezo Electronics/Wiring Thread

Nice F Holes

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I just started working on the electronics of my SE HB Piezo. I’ll post some pics and stuff but wanted to ask if there’s anything specific people want to see or know. I’m not great at organizing threads and pics but I’ll do my best. I’m totally open to mods or anyone else editing this if it turns into something useful.

It’s going to take a little while, since being particular and living on an island don’t go well together!

What I’ve learned so far:

*The pots have 3/8” shafts!!! USA (imperial) pots fit the holes!
*Pots are: Alpha B500k ?! (linear volume); Alpha A500k (tone); Unknown B25k (Piezo.)
*The pots have coarse splines, so changing to USA pots means new knobs, if you’re particular.
*Push-pull will fit where the Piezo tone pot is (checked Dimarzio and CTS.)
*Push-pull fits under volume, but I feel it’s not a sturdy area being that close to the F-hole.
*Smaller push-pulls (not CTS) fit through battery hatch. CTS would have to go through pup cavity.
*Piezo is a B25K linear pot. It says <O>. DI YA. 1917. And also B25K.
*Piezo board has to be removed to take out the tone pot.
*Push-pull will NOT fit below tone pot, due to Piezo PCB.
*Tone cap is .022uF, not typical .033 PRS tone cap
*No treble bleed cap.

I noticed the pot washers were completely corroded - as in disintegrated. Also my switch isn’t working right. Then curiosity took over, and now this is an effort to:
*Change pups to 57/08
*Change pots to CTS (and DiMarzio push-pull.)
*Change switch to Switchcraft
*Install treble bleed
*Change tone cap value
*Swap tone and piezo volume pots and install push/pull tone for (partial) coil split

Again, LMK if there’s anything you wanna see! And thank you all for being here, this is one of the best forums on the web.

Edit: the pictures in the post below disappeared, so I'm adding what I can find here. It's been almost 3 years so I don't know what's missing.

Here's the original wiring harness. The soldering wasn't very good.
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The pots for the mag volume and treble:
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The board for the Piezo electronics:

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Underside of the Piezo bridge:
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Some pics of the insides of the guitar:
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Pickup cavities:
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Fit check of 3/8" pot through stock pot holes:
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Interesting combination of parts makers. Di Ya must be Chinese (never heard of them) but the tone push-pull is the trusty Noble pot (fantastic quality Japanese firm). Can’t believe the oxidation on those washers. Where do you live?

Nice reveal. Thanks!
 
I don't really understand how push-pulls get wired, but is it possible to put a push-pull on the piezo knob for the purpose of splitting the bridge pickup? Or do push-pulls only work on things that are going through that knob anyway?
 
@Hotspur push pull is a switch mounted under a pot. The put shaft activates the switch but they are electrically independent. It’s a double pole switch so it can control 2 devices, therefore both pickups can go to coil split with 1 switch. Typically

Unfortunately the piezo potentiometer is an odd value and it’s hard to find 25k push pulls. So I’ll move the piezo pot where the tone is, and the tone control will be where the piezo is, so the push pull tone will fit and control both pup coil taps.
 
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@Boogie the push pull is my pot that I’m installing.

And thinking about this a little more, I think the oxidation is from sweat, and cheaply coated hardware. There was a day early on when I played that was really hot and the guitar got pretty wet. I wiped and cleaned it, but not under the knobs.
 
The 25k linear pot with coarse splines is a little challenging. It’s hard to find 25k linear with fine splines. I’m particular so having pots with different shaft sizes doesn’t sit well with me, not on a guitar like this. So, the OCD got the best of me and I ordered a nice CTS 500k pot, and a CTS 25k linear amp pot, and will swap the wafers.

I also really like the feel and (lack of) sound of this Dimarzio push-pull, so I ordered another Dimarzio pot for the magnetic volume.

So, this project won’t be done this weekend. Hopefully parts from StewMac get here next week, but I’m on a small rock in a big ocean, so we’ll see...

In the meantime I guess I can do the pickup swap, swap the switch, stick a cap on the existing volume pot, and maybe do the push-pull. I ordered a nicer .330 uF cap for the tone so I’m not sure if I want to work on that pot twice or not.
 
Here's the entire wiring harness. It has a linear volume pot! The volume and tone pots are Alpha; I updated the first post with that info.

There's nothing really special or fancy about the wiring, just that the output from the volume pot is soldered to the PCB rather than directly to a 1/4" jack.

I will say, be considerate of your luthier if you have one work on this guitar. There are tons of little clips inside to keep the wires tidy, and they require a LOT of patience to deal with.

You can see the B500k in the pic below - that should be an A500K pot.

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@Hotspur push pull is a switch mounted under a pot. The put shaft activates the switch but they are electrically independent. It’s a double pole switch so it can control 2 devices, therefore both pickups can go to coil split with 1 switch. Typically

Unfortunately the piezo potentiometer is an odd value and it’s hard to find 25k push pulls. So I’ll move the piezo pot where the tone is, and the tone control will be where the piezo is, so the push pull tone will fit and control both pup coil taps.

If you're not putting independent coil-tap switches in, couldn't you just, then, put the push-pull under the volume knob and not deal with moving knobs around?

I'm very curious to hear how this sounds with the taps in.
 
@Alnus Rubra I will if it’s not too much trouble. I don’t play through a pc or anything so we’ll see, but I would like to be able to post something.

I kind of wish I corrected what was wrong so I could hear it the way it’s supposed to sound...but I’m sure I won’t be disappointed with the changes.

@Hotspur im concerned the volume knob is too close to the F-hole. The wood flexes a little if you push there. PRS core guitars use the tone knobs, and they do a toggle mod, but there’s not much experience using the volume pot location for push-pull. So I’d rather play it safe.
 
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Hm. Interesting.

I guess the alternative is installing a couple of mini-toggles if you want independent coil-tapping. Let us know how you feel about the coil-tap sounds. I love the split-sounds out of those pickups in the S2 594.
 
That goes along what I’ve been thinking: I want to see if I like it before drilling the guitar. If I’m happy with it, I’ll likely install a toggle. I’ve never been happy with split sounds before, but also never tried pups this nice and with PRS resistor values.

Though personally, the only split tone I like is with both pups active. So I’m not too worried about individual pup splitting.
 
I'm kind of torn between:
a) reassembling with a working switch, audio taper volume pot, and treble bleed to get a new baseline, or
b) doing the whole thing with the new pickups and switch, to have what I want and avoid rework.

Thinking about it, I guess there's also:
c) do a temporary install of a. with the electronics mounted externally on a board...
 
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