HSH configuration 920D P-rails style troubleshooting questions

matei

New member
Hi everybody, I am new to the forum and looking at my first wiring ever.

I am putting together a HSH pickguard for a strat with push-pull pots. The wiring copies what the guys from 920D do in their build (https://www.siglermusiconline.com/products/920d-custom-loaded-strat-pickguard-with-seymour-duncan-hsh-p-rails, 4th picture shows the wiring)

I have the following pickup configuration: Neck humbucker size P-rail SHPR-1N; middle Vintage rail SVR-1n; bridge: trembucker P-rail TBPR-1
I ended up using a .047 cap for tone control because the wiring diagram shows it. I figured out later that the pictures of the actual wiring show a 0.022 cap.

I am at the moment at screwdriver tapping and troubleshooting. And I have noticed the following aspects:
- With the rails selected, tapping on the P-90 poles produces also a tap sound. Same when the P-90 is selected and tapping the rails.
After a bit of research I found out one mention on a forum that this would be normal. Can anybody confirm this?

- Noticed that the middle pickup (SVR-1n) is wired in parallel according to the wiring diagram with the rd/black wires on the hot and the green white bare wires on the ground side.
Is this the way it is supposed to be done?

- With all pickups in humbucker series mode, in positions 1, 3, and 5 when tapping on the pole pieces I get a response with equal intensity on all three pickups (let's say intensity 1.0)
When I go in position 2 and tap the neck and the middle pickup, the neck pickup is half as loud as in position 1 (0.5 intensity) but the middle pickup is as loud as as when in position 3 (1.0 intensity)
Same thing happens when I go in position 4 and tap the middle and the bridge.
Is this normal? and if not how can I troubleshoot it?

Kind regards,
Matei
 
Re: HSH configuration 920D P-rails style troubleshooting questions

I am coming back with new info. I measured the DC resistance between the hot and ground of the output jack.
First picture shows a comparison between the measured values and the datasheet of the pickups. It also has the calculated values for series / parallel connections
Nominalvalues.JPG

Then I went through all the positions of the selector and all the parallel / series configurations. The field series / parallel / p-90 / rails indicates that the humbuckers are set to that configuration individually.

SelectorPositions.JPG

I can make a guess but it would be great if anybody can confirm my feeling: When I select Neck + Middle, with the neck having the coils in series, the impedance difference is so big (12.73 compared to 2.581) that most of the signal will come out from the middle pickup. Am I on the right track?

Also what do you think about the Neck + Bridge configuration with the humbucker coils in seris (it shows 100 ohms less than it should be)?
 
Re: HSH configuration 920D P-rails style troubleshooting questions

Hi,

I am intrigued by the fact that nobody has anything to say to my question.
I am a real beginner so I have no problem with answers like "this is really stupid because ..." but any information will be appreciated

Regards,
Matei
 
Re: HSH configuration 920D P-rails style troubleshooting questions

Welcome to the forum.

1% off the dcr is normal and really indicates that everything is working right. Does everything sound right?
 
Re: HSH configuration 920D P-rails style troubleshooting questions

Hi @Clint 55

Thank you for your reply (and the good news). I can't really tell you if everything sounds right at the moment because I am finishing the body and the neck. Meanwhile I thought it would be a good time to put the electronics togehter

Regards,
Matei
 
Re: HSH configuration 920D P-rails style troubleshooting questions

Hi everybody,

I managed to finish the guitar to the level I can test the electronics.
I faced the following problem:
The bridge pickup wired (Black -> White -> Red -> Green -> Ground) Was having a very quiet output. After a bit of investigating I figured out it has to be something out of phase with itself. I reversed the Red Green pair and fixed the problem.

Now whenever I touch with my hand the rail it generates a buzz. The neck pickup does not buzz at all. What would be wrong?
 
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