Have hooked up my wiring, but getting some odd phase issues

[wollyroger]

Hi folks,
 
I'm hoping someone can help (I know a little about guitar wiring, but not enough!)

I have just finished modding my Schector Nick Johnston, but am getting some odd results...

Here is a rough wiring diagram:






Components are:

the 2 original neck and middle single coils that came with the guitar
a new dimarzio transition bridge humbucker
schaller megaswitch E
Shadow 250k volume / kill switch (forgot to include the switch on the diagram, but it is wired as suggested by the manufacturer, basically signal to one lug, ground to the other)
Allparts push pull pot (used as tone control and humbucker coil split)

I'm having two problems. 

Firstly, when the Shadow volume pot is connected to the megaswitch the killswitch no longer works. 

Secondly, the middle and bridge/middle positions of the pick up selector switch result in an odd 'out of phase' sound. Please see videos here:

drive.google.com/open?id=1kLWRvQNF3q6W4_q9wQFcqlpTQHeGzCEH&usp=drive_fs

Are these components compatible? 

When I test continuity with a multimeter I noticed I am getting signal going to ground from the hot connectors (a short, but I can't see an issue with the wiring or hear a problem when the guitar us plugged into an amp). This doesn't happen when I take the megaswitch out of the circuit. I'm wondering whether I might have a dodgy megaswitch...?

Thanks in advance, Rog

[reTrEaD]

Hello, wollyroger and welcome to Guitarnuts2.

Near as I can discern your diagram is based on Shaller's HSS5 from the link below but has been modified for a single master tone control and an added split switch for the HB. The HB should automatically split to single-coil mode in positions 2 and 3 because of the megaswitch so the only need for it would be to split the HB in position 1 (bridge only).
schaller.info/en/megaswitch-e

Let's solve the out of phase issue first, then circle back to the killpot afterward.

It's possible the magnet has been flipped on your HB, but if so, that will be kind of a pain to disassemble and correct, so we won't go there unless absolutely necessary. The colors you're using on the HB are correct for a DiMarzio. But the out of phase issue only occurs when either of the two SCs are combined with a coil from the HB.

Exchange the roles of the red and black wires of your SC pickups.
Reds will connect to ground.
Black from the Neck pickup will connect to lug-2 of the megaswitch.
Black from the Middle pickup will connect to lug-1 of the megaswitch.

Confirm that corrects the out of phase problem, then we'll continue.

[wollyroger]

Hi retread,

Thanks for the reply 👍🏻

That's exactly right, the current wiring is based on the HSS5 wiring. I did initially attempt to wire the hot of the HB to both positions 6 and 7 on the megaswitch to give me the HB on positions 3,4 and 5 (which I could then switch to SC using the push pull pot), but I got the out of phase sound on position 3 and silence on position 4, so figured this might not be possible, so reverted to the wiring on the Schaller website.

I will have a look at your suggestion this morning and report back... ✌🏻

[wollyroger]

Hi retread,

So, have swapped the hot and ground wires on both SC and success...! The pickups are working as intended. What's more, the killswitch is now working too 👍🏻

Do I need to reverse the magnet on the HB, or will this workaround do?

I'm trying to get my head around the theory of why this wasn't working and now is...! 🤯

Only thing I'm not sure about is the sound from position 3. It is quite 'glassy' (as it is using the bridge-side coil of the HB). Also, when the coil split is engaged this position is silenced...

If I were to use my original idea of wiring the hot to both lugs 6 and 7 of the megaswitch would this give me the switchable bridge HB/SC across positions 3,4 and 5...?

Sorry for all the questions and thanks for your help so far 👍🏻

Rog

[reTrEaD]

Hey wollyroger , sorry for the delay in getting back to you. I had a lot on my plate before, during, and after the holiday.

Nov 21, 2023 5:14:53 GMT -5 wollyroger said:

Do I need to reverse the magnet on the HB, or will this workaround do?

There's no need to flip the magnet on the HB. We don't know if that was the original problem and even if it was, we compensated for it by changing the electrical polarity of both of the SC pickups.

Nov 21, 2023 5:14:53 GMT -5 wollyroger said:

I'm trying to get my head around the theory of why this wasn't working and now is...!

Not sure why the killswitch wasn't working but I can explain the out of phase issue.

Whether a pickup has a positive-going signal (or a negative-going signal) when the strings move toward the pickup, depends on three things:
1 - The orientation of the magnet. North-seeking pole end, or South-seeking end down.
2 - The winding direction. Clockwise or counter-clockwise.
3 - Which end of the winding goes to hot. Finish to hot or start to hot.

Many pickup manufacturers (including, but not limited to Seymour Duncan and Dimarzio) choose to label their wires such that the 'hot' produces a positive-going signal when the string moves toward the pickup. Either the Schecter pickups are made such that the signal goes positive when the string moves away from the pickup OR the magnet is flipped on the DiMarzio HB (meaning the signal will go positive when the string moves away from the pickup). Because of that, the signal was out of phase whenever one of the SCs was combined with one of the coils of the HB. We don't know which of these was the case but we've compensated for the disagreement.

Nov 21, 2023 5:14:53 GMT -5 wollyroger said:

Only thing I'm not sure about is the sound from position 3. It is quite 'glassy' (as it is using the bridge-side coil of the HB).

If we look carefully at the wiring of HSS5, we can see that the bridge-side coil of the HB is supposed to be active in position 2 and the neck-side coil of the HB should be active in position 3.

I believe their choice of combinations took tone and hum-canceling into account. The if the Neck pickup has a North magnetic polarity and the bridge-side coil of the HB has a South magnetic polarity, they will hum-cancel when combined together in-phase. Since the Neck pickup has a strong fundamental in relation to the harmonic content, this will balance well with the high degree of harmonic content from the bridge-most coil of the HB.

Likewise the South magnetic polarity of the middle pickup will hum-cancel with the North magnetic polarity of the HB, when the two coils are combined in-phase.

But that's not how you have the HB wired. This is not a problem for the phase relationship between the DiMarzio and the Schecters but it will affect hum-canceling and the tone. The bridge-side coil of the HB will sound better when combined with the neck pickup.

We need to either spin the HB 180 degrees or change the way the HB's coils are 'stacked' in series mode. But we'll need to determine the best course of action to get hum-canceling when the coils are combined together.

Nov 21, 2023 5:14:53 GMT -5 wollyroger said:

Also, when the coil split is engaged this position is silenced...

Referring again to the HSS5 drawing, we can see that the series link of the HB is connected to pad 6 of the megaswitch. This is connected to the output (pad 3) in position 3. When you connect that to ground via the push-pull, all signal is shunted to ground. To avoid that, we'll need to be a bit more clever about how we connect pad 6, the push-pull, and the series link. Exactly how we accomplish that will come later, after we decide how to get the bridge-side coil of the HB paired up with the Neck pickup and the neck-side coil of the HB paired up with then Middle pickup.

Nov 21, 2023 5:14:53 GMT -5 wollyroger said:

If I were to use my original idea of wiring the hot to both lugs 6 and 7 of the megaswitch would this give me the switchable bridge HB/SC across positions 3,4 and 5...?

No, that won't work. It will shunt all signal to ground position 2 via lug 4.

---

Our next step forward begins with determining the magnetic polarity of all 4 coils and/or evaluating the hum-canceling in all 5 positions with the present wiring.

We should expect position 5 (neck only) to have the most hum and position 1 (HB) to have the least. How much hum is present in positions 2, 3, and 4?

Also, you can place a compass near the face of each of the 4 coils, and note which end of the needle is attracted to each of the coils. I would expect the Neck pickup and the slug coil of the HB to attract the 'South' end of the compass needle. The Middle pickup and the screw coil of the HB should attract 'North' end of the compass. But you should verify this or tell me what results you actually get.

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Once I have this information, I can probably rework the wiring to get better tone choices in positions 2 and 3, and have those positions hum-cancel, and create a strategy where the push-pull will not kill the signal in any of the selections.