ChrisK brilliance __||

[unreg]

Hi 🙂

This is excellent! 😀❤️

Sept 9, 2009 20:42:16 GMT -5 ChrisK said:

While one can tell if a pickup is active by pole tapping, one cannot tell the inter-pickup wiring structure.

While I have no patience to sus out the pickup inter-mingling aboot in your 5-way switch (both poles have shorting effects as well as pickup selection effects), I would suggest that this be done.


For a short-cut way of "seeing" what is amiss and a'muck, I would propose that you replace each pickup with a binary multiple fixed resistor.

Bridge 1 K Ohms (two 2 K Ohms in parallel)
Middle 2K Ohms (one 2 K Ohms)
Neck 4 K Ohms (two 2 K Ohms in series)

This can be realized with 5 resistors, coincidently the number in a pack of 5 from Radio Shack.

Buy 1% resistors if you can.

One can then easily determine the inter-pickup wiring structure from simple resistance measurements at the output jack. Ensure that the volume and tone pots are all at their full clockwise rotation.

Two (or more) resistances in series add, two (or more) resistances in parallel are related like this; Series and Parallel Components.

I do this to initially check out EVERY wiring effort that I do. Simple is.

Sept 9, 2009 21:35:51 GMT -5 ChrisK said:

Methinks I may be out of my league 'cause I really don't understand how to do what you've outlined.

Ok, now pay attention.

I would propose that you replace each pickup with a binary multiple fixed resistor.

Buy 1% resistors if you can. Buy nothing worse than 5% tolerance resistors.

Bridge 1 K Ohms (two 2 K Ohms in parallel)
Solder two 2 K resistors in parallel and connect them where the bridge pickup's two wires went (remove the bridge pickups wires from the switching circuit).

Middle 2K Ohms (one 2 K Ohms)
Solder one 2 K resistor to where the middle pickup's two wires went (remove the middle pickups wires from the switching circuit).

Neck 4 K Ohms (two 2 K Ohms in series)
Solder two 2 K resistors in series and connect them where the neck pickup's two wires went (remove the neck pickups wires from the switching circuit).

If you measure 6 K Ohms at the output jack, the middle and neck pickups are in series. If you measure 1K33 Ohms at the output jack, the middle and neck pickups are in parallel.

One can easily determine which pickups are selected, and in what structure with this test approach.

If you measure the resistance at the output jack with all volume and tone pots at full clockwise rotation and post the readings, we can trivially ascertain which pickups are selected, and in what structure.


I do this to initially check out EVERY wiring effort that I do. Simple is.

I'm considering just trying the standard strat wiring, just to see if I can get that to work.

EDIT: is from this thread:

guitarnuts2.proboards.com/thread/4430/wiring-help?page=2#post-39552

—-
General ?: How are resistors wired in parallel? Series is just one connected to the other (in a line) right?

[b4nj0]

Lay the (eg) resistors side by side, and solder or twist the legs at each end together. You now have a configuration that has two components having only one connection at each "end". Series is like an end to end daisy chain. You can of course have combinations of the above.

e&oe ...

[ashcatlt]

This whole thing is only really necessary if the coils themselves are too similar to be told apart reliably by measurement, and even then most of the time only for more complex wirings. With fairly typical pickup set that are deliberately mismatched, we can usually figure it out as long as we know the DC resistance of each.

[Yogi B]

Oct 9, 2021 12:37:57 GMT -5 ashcatlt said:

This whole thing is only really necessary if the coils themselves are too similar to be told apart reliably by measurement, and even then most of the time only for more complex wirings

Additionally for really complicated wirings it's not completely infallible either, as pickups aren't binary — there's more than one way they can be 'on', for instance:

\def\k{\mathrm{k}}

(((1\k \parallel 4\k) + 8\k) \parallel 16\k) + 2\k
= {238\k \over 31}
= (1\k + 16\k) \parallel (2\k + 4\k + 8\k)

[unreg]

This ChrisK math idea is extremely simple for most people to find out if their wiring is series or parallel. That’s what makes it brilliant to me! 😀


From my first ChrisK-quote’s link:

Sept 9, 2009 21:21:22 GMT -5 ChrisK said:

Resistance

Resistances in series add.

Rt = R1 + R2 + ... Rn


Resistances in parallel are calculated this way.

Rt = 1/[1/R1 + 1/R2 + ... 1/Rn]

For two resistors;

Rt = [R1 * R2]/[R1 + R2]

Therefore, middle (2k) neck (4k) in series gives 2k+4k=6k resistance reading. And those in parallel give (2k*4k)/(2k+4k)=8k/6k=1k33 resistance reading.


So, if you only have two pickups you could use like 3 2k resistors; just do the simple math to see what value you’re looking for. 👍


It’s so simple and would be helpful for me… and maybe thetragichero, he talked about not noticing his pickups weren’t wired in series, I think. Good brilliant simpleness in ChrisK’s idea! 😊

[thetragichero]

unreg say what now?

[b4nj0]

It is a good basic approach from ChrisK, but it's more a case of proving Ohm's law than identifying pickup topology isn't it? To accomplish it is necessary to first go inside, secondly temporarily eliminate the pickups and thirdly put in resistors. At that point of the surgery, anyone can just look at the wiring (and sketch it down if need be.) If no labeling or sketch is made, there's always the 50:50 chance the pickups might go in A over T, and those odds don't change in your favour if you have coil split wiring.

In any parallel arrangement of resistors, the resultant value is always less than the lowest value of resistor, so even with the pots turned to the extreme of being effectively out of circuit, I wonder about that unless you have no load potentiometers. In short it seems to be a theoretical exercise to me, but as ChrisK would acknowledge, if'n I'm shootin' feldegarbe, plenty of folks on here will step up to save me from the ignominy of persevering with that viewpoint? (in other words, basically I'm theorising too!)

Edit: Also, this will only be reliable if a meter with in excess of 20K Ohms/Volt is used, otherwise the meter will load the circuit and the readout cannot be relied upon. Any digital readout meter will be fine, but a needle meter needs to be much more sensitive than a 5 bucks Radio Shack job.

e&oe ...

[newey]

In any parallel arrangement of resistors, the resultant value is always less than the lowest value of resistor, so even with the pots turned to the extreme of being effectively out of circuit, I wonder about that unless you have no load potentiometers

One can use this same technique, as ChrisK himself explains, to ascertain the resistance values of the pots (within their tolerances, of course), and the pots can then be "factored out" of the equation, as he showed here

[b4nj0]

I've looked and cannot see where ChrisK explained about using the same technique to provide for the pots, but of course that's my own omission. If you have the understanding of such complex series parallel arrangements to do that, I suspect you have no need to go down this route anyway?

During the course of wiring up a circuit (which may involve remedial work, personal inspiration, or understanding someone else's vision, I think I'd ring out the switch(es) and go from there. It was indeed a brilliant notion from ChrisK, and his kind of blue sky thinking comes along but once in long while, but I cannot envisage a scenario when I'd feel compelled to go those extra few furlongs to arrive at the same post.



e&oe ...

[unreg]

Oct 10, 2021 13:18:06 GMT -5 thetragichero said:

unreg say what now?

Oh, um, I remember reading you say that one of your guitar projects, maybe the first one, you wired the pickups in what you thought was parallel. Much later you found out the wiring was actually series… and so you said you had a new appreciation for the parallel sound.


I realize what I just stated is exactly opposite from what confused you. Sry. And, maybe it wasn’t even you 😔; but, I did read someone’s post about that on this forum. 🙂

[thetragichero]

nah the middle pickup was out of phase with the bridge and neck. all positions parallel because it was a standard 5-way switch. parallel out of phase will still read 'normal' with a dcr measurement. the 'screwdriver pull off test' is what helps diagnose whether two pickups will be in phase. this was not in my box of tricks at that time

[unreg]

Ahh, of course your bag box of tricks wasn’t full bc you just started. 👍 It was a parallel in-phase appreciation instead of a parallel appreciation; sry for remembering wrong. Thank you for correcting me! 🙂