Another Monster P-Rails Thread

[Bacchus]

Hey folks, I've been reading on here for a while and the time has come for me to post, having struggled for a week or so trying to sort out a guitar with two P-Rails.

Basically, I want it all. I want to be able to choose between each coil on each pickup, to be able to combine each coil with it's partner in series/parallel as well as in/out of phase. I also want to be able to control how I put each pickup against the other in either series/parallel and in/out phase.

Oh, and I'm using stacked knobs so that I have control over the volume and tone on each pickup.

After a lot of reading, I found the rather excellent 1728.com which provided a lot of information on switching. I decided to take the "Super-7 Switching" from that website and modify it so that I would have control over phase as well as series/parallel. Below is the wiring diagram I came up with.

I've wired it together, checked everything, taken it apart, rewired it, checked everything, and taken it apart again. At no point have I been able to get it working correctly. All wires are good, shielded wires, and are have insulation outside the shielding, so there are no shorts or anything.

I'm at my wits' end, now, and any help is massively appreciated. I don't mind steep learning curves, but I don't mind that so long as I know I'm not wasting my time with a dodgy diagram.

TL;DR: I have two key questions with regards the following diagram.

1. Are the pots wired correctly, and in the correct place in the diagram? (the pots are represented by the yellow boxes so as to save space and are wired as shown in the yellow box on the left)

2. Is the rest of the diagram as it should be? One particular area of concern is the phase switching and whether or not that is correct.

I will have a varitone in this guitar eventually, but I'm still waiting on inductors for it to arrive, so it hasn't been built or fitted, and should be disregarded. If anyone has any other questions about why certain things in this diagram are the way they are, I can answer them. I realise that the diagram might look like a confused mess but there is a reason (right or wrong) why I put everything where it is.



Thanks!!!

[DrNewcenstein]

What is it not doing that it should be doing? Or, what is it doing that it should not be doing?
You haven't said what the problem is.

[Bacchus]

Thanks for your reply.

The weird thing is that the circuit isn't misbehaving in predictable ways. For instance, the neck phase switch seems to act like a master switch. Touching polepieces on the neck with a screw driver gives a loud pop even when the neck is supposed to be disengaged.

Also, I'm getting an awful lot of noise which would suggest that there's a grounding problem somewhere, but that I suspect that's a secondary problem.

However, I am not looking for help troubleshooting my wiring, I can fully accept that I've made a mistake soldering it together and am happy enough to keep working at everything myself, but I'd like to know that the diagram is a good one in case I waste more hours at this then find out that it was never going to work with this diagram anyway.

Does the diagram look good to you?

Thanks.

[Bacchus]

Anyone?

[frobro808]

hehehe funny story the same thing happened to me when i installed my p-rails w/ triple shots + system series/parallel + phase switch. i wired the jack backwards. it was my first solder-job ever. the noise and backwards switching sounds really familiar. did you check the jack?

[Bacchus]

No-one?

To be clear, i'm not looking for any help here beyond a simple yes/no answer from someone who is better at understanding switching than I am.

[Bacchus]

No?

Ah well, thanks anyway, folks.

[DrNewcenstein]

I also want to be able to control how I put each pickup against the other in either series/parallel and in/out phase.

Ok, we'll take this step by step:

First, with this comment, are you saying you want to be able to control whether the neck is phased with the bridge or the bridge is phased with the neck (switch one way and the neck is out of phase with the bridge, flip it another way and the bridge is out of phase with the neck)?

That will not make one bit of tonal difference. Out of phase is out of phase, regardless of which pickup is flipped.



As for your diagram, I can't see anything wrong offhand since you do have wires going to each contact.

What I can see that might be an issue is you haven't labeled anything in the diagram except the pots, so any sort of troubleshooting assistance cannot be given easily as "sw1, sw4, etc".

So in light of that, I'll simply say that your left mini toggle coming off the bridge has one contact (green) that when engaged will cut straight to another switch that when engaged will shunt to ground.

If this is your intention, then there's no problem.


If the neck is not putting out string sound, only reacting when touched by a metal object, then I'd say it's either a ground issue (the bare wire) or you're linked to the other pickup through one of your switch options.

I would say start with one pickup at a time, from beginning to jack, and make sure everything's working the way you want it for that pickup (series/split-parallel), then disconnect it from the point where the other pickup will join it and wire that one up, checking the functions along the way.

Once both pickups are doing individually what they need to do, move both to the next shared point and wire that straight to the jack (i.e. phase, or whatever). Once that's working properly, move to the next piece (neck rail in series with bridge rail, for example) and run that out to the jack to ensure it's working.

Keep going like that until you've got it all set.

If you find any problems along the way, come back and we'll focus on that -it could be you've got the wrong switch for the job (SPST instead of SPDT, etc), it could be you've left a test connection in place, or it could be that you've simply got two switching options canceling each other out (the aforementioned wire).

But, as I said, the diagram looks ok to me except for that one green wire going to a switched ground option.

[Bacchus]

Thanks for your reply, it's very helpful.

I've neglected to point out that all switches here are either SPDT or DPDT and are all "'no-centre" switches. Also, I've chased down the grounding problem now and the circuit is as quiet as it should be.

Ok, we'll take this step by step:

First, with this comment, are you saying you want to be able to control whether the neck is phased with the bridge or the bridge is phased with the neck (switch one way and the neck is out of phase with the bridge, flip it another way and the bridge is out of phase with the neck)?

That will not make one bit of tonal difference. Out of phase is out of phase, regardless of which pickup is flipped.

My intention is that the middle DPDT switch control phase between the two pickups so that they are in phase when the switch is one way and out of phase with the switch the other way. You'll notice the outside terminals are jumpered in an X arrangement to achieve this. This entire diagram is effectively the same switch set repeated three times, if that makes sense.

As for your diagram, I can't see anything wrong offhand since you do have wires going to each contact.

What I can see that might be an issue is you haven't labeled anything in the diagram except the pots, so any sort of troubleshooting assistance cannot be given easily as "sw1, sw4, etc".

So in light of that, I'll simply say that your left mini toggle coming off the bridge has one contact (green) that when engaged will cut straight to another switch that when engaged will shunt to ground.

If this is your intention, then there's no problem.

Hmm, I'm not entirely sure about this bit. I will point out here that my diagram is adopted from 1728.com's Super-7 switching diagram. Annoyingly, this website seems to be experiencing some sort of difficulty and I can't access it to post the diagram here. I can describe how the original circuit is supposed to behave, however. The original circuit taken from 1728 had six SPDT switches (three sets of two). There was a set of two for each pickup, then one master set in the middle, allowing each coil in a humbucker to be placed with the other one either in series or parallel, and the middle one would do the same but between the two pickups. Each set of two switches behaved roughly as follows:

Where S means switch and C means coil (or pickup in the case of the middle set of switches):

S1 up, S2 down : C1 on its own
S1 down S2 up : C2 on its own
S1 up S2 up : C1 and C2 in series
S1 down S2 down : C1 and C2 in parallel


I've then taken this set up and tried to introduce phase switching by putting it before each of the banks of two switches so that I can put C1 and C2 of particular pickup in or out of phase with the rest. Dunno if that clears anything up or makes the diagram easier to make sense of.

If the neck is not putting out string sound, only reacting when touched by a metal object, then I'd say it's either a ground issue (the bare wire) or you're linked to the other pickup through one of your switch options.

There is string sound but it doesn't sound particularly like anything, if that makes sense. It doesn't sound very much like a neck pickup or very muck like the bridge or it doesn't ever sound very much like a single coil. It sounds like I'm getting a messy, undefined humbucker sound, if you know what I mean.

I would say start with one pickup at a time, from beginning to jack, and make sure everything's working the way you want it for that pickup (series/split-parallel), then disconnect it from the point where the other pickup will join it and wire that one up, checking the functions along the way.

Once both pickups are doing individually what they need to do, move both to the next shared point and wire that straight to the jack (i.e. phase, or whatever). Once that's working properly, move to the next piece (neck rail in series with bridge rail, for example) and run that out to the jack to ensure it's working.

Keep going like that until you've got it all set.

That is sounding like the most logical way of doing this. If I can't get it working at the next attempt I think I'll start taking it apart like this.

If you find any problems along the way, come back and we'll focus on that -it could be you've got the wrong switch for the job (SPST instead of SPDT, etc), it could be you've left a test connection in place, or it could be that you've simply got two switching options canceling each other out (the aforementioned wire).

But, as I said, the diagram looks ok to me except for that one green wire going to a switched ground option.

That is sounding like the most logical way of doing this. If I can't get it working at the next attempt I think I'll start taking it apart like this.

The switches I ordered were six SPDT and three DPDT, I'd be pretty annoyed at my supplier if they were wrong, but it's worth thinking about too, I suppose.