Wiring with phase, series / parallel, pickup selec

[hajamie]

Hi, I am currently half way through building a guitar, and I'm trying to work out how to wire it. I have designed this circuit which (I think) will allow me to select pickups, have the pickups wired in series or parallel, have the pickups in or out of phase and change the tone for all three pickups independently(ish). Only thing is, I'm not sure if it will work.
Here are a couple of diagrams (of the same circuit). I'd be eternally grateful if someone could tell me if it will work (particularly the tone controls).
Thanks,
J.




N.B. When the circuit is switched from series to parallel the phase of the middle pickup is also changed (but this could be counteracted with the middle phase switch).

[JohnH]

Hi hajamie - welcome to GN2.

That is a very clearly presented circuit, and certainly worthy of a careful check by the nutz. Ive not checked it through, but I will say that the series/parallel switching of SSS is a problem that many have tackled. My version needed a four pole toggle instead of three poles as you have:

guitarnuts2.proboards45.com/index.cgi?board=schem&action=display&thread=1130243150

So im curious to see how you have done it! The things to watch for are unwanted dead spots and 'quirky'settings.

As to tones, it would be better to wire them directly across the respective pups, that way they stay independent in all modes.

cheers

John

[hajamie]

Hi, thanks for your reply. How would I wire the tone controls across the pickups? This is the part I don't really understand - I get the idea that the caps resistance varies with frequency, but I'm not to sure how it all goes together. Could I wire a pot and cap in series across each pickup?

This is my basic idea for series / parallel switching. This third part of the switch is to allow the on off switch for the Lower pickup to work.
www.nugit.co.uk/series parallel.GIF[/img]
When the pickups are turned off in parallel, they have to be disconnected from the circuit at one end, whereas in series they have to be shorted (or shorted and disconnected at one end). I managed this with the top pickup in the above diagram and the diagonal one by connecting them to the top right pin of the switch when disconnected (as this does not form part of the circuit in parallel mode. However I couldn't find a way to do this with the lower pickup, so I added another pole to the switch (if the initial switch was seen to be made up of two switches, this one is now three). This diagram might explain this better:

The above diagram is wired differently to my initial diagram. In my initial diagram I add another pole in the middle, whereas in this one I added it to the left.

[michaelcbell]

hajamie,

I've taken a look at your wiring, and given the caveat that you propose at the end of your first post about the mid pup phased in parallel mode, your circuit does what you intend, for the most part. Congrats! The issues I do see: 1. Nearly every pup that is not engaged is hanging from hot, which COULD cause tone 'loss'. Search this forum for 'hanging hot' over the last 200-300 days and see what you come up with. 2. You very much need to wire your tone controls across your pickups as the wiring scheme you have now will cause significant funkiness in numerous positions due to hanging hots being connected to ground THROUGH a tone pot, giving you a low-cut series combination. This may be a cool thing when planned for, but the issue I see is that it is a little too unpredictable in this configuration to be useful. Just my thoughts.

[michaelcbell]

and yes, you would wire a pot and cap in series with each other, in parallel with the pup.

[JohnH]

I think that is clever, and ecconomical on switch poles.

One issue to watch out for, since the pups are generally only disconnected from one side, if the pup is left connected to the hot output, it may still pick up a little noise even though it makes no sound. A good shielding job may fix it however. The all off setting is likley to be the noisiest in this regard.

For the tone controls, to change the first diagram, just take the wires from the tone caps that are going to ground, and instead connect them to the top right lugs of the respective phase switches.

The caps act to pass high frequencies more than low frequencies, hence shunting the highs, reducing treble. Doing this through the variable resistance of the tone pots varries the effect.

John

[hajamie]

Thanks again for the help.
Firstly, having read through some of the topics on hanging hots, it sounds like this won't be a problem as long as I shield the thing properly (which I intend on doing).

Second, I've wired the tone controls incorrectly. Here is a revised diagram.
www.nugit.co.uk/circuit rev2.GIF[/img]
I decided to buy no load pots for the tone controls because it seemed like a good idea. If I wire them as above, will they work as intended?

Thanks,
J.

[hajamie]

John, I noticed on your diagram that you say it has a silent off. To stop buzzing when all pickups are off, would I have to have both terminals of the output jack wired together?
Thanks,
J

[sumgai]

Chris,

Point of grammer.......

Is it correct to say "Ambitions are", or must I say "Ambition is"?

;D


sumgai

[JohnH]

hajamie said:

John, I noticed on your diagram that you say it has a silent off. To stop buzzing when all pickups are off, would I have to have both terminals of the output jack wired together?
Thanks,
J

An all off position with output connected to ground will be dead quiet, while a disconnected one will probably buzz.

The hanging hot issue will be improved by shielding, but may not be eliminated since the pups are outside the shielding - just watch out, if you hear a slight buzz. It does not affect the actual tone, but I prefer to avoid it. The opposite condition, of connecting one end to ground is no problem.

John

[ChrisK]

Is it correct to say "Ambitions are", or must I say "Ambition is"?

Well, I must say ambition is.

In the latter, it is a force (and may it be with you).

In the former, they are vectors, in multiple forceful directions.

I certainly hope that this clearly obfuscates the issue for you.

[hajamie]

Ok, I think I've cracked it! Seen as I have bought dpdt switches for the pickup selection, here is a revised circuit which, as far as I can see, does everything I want and does not leave pickups dangling all over the place. I think this should make it nice and quiet whatever is selected.
www.nugit.co.uk/circuit rev3.GIF[/img]
If anyone is interested, here are the switches I'm using for pickup selection:

Here are the ones I've got for phase switching:

My series / parallel switch is just a boring (but shiny) toggle switch.
I'm going to mount these on a polished stainless steel scratch plate (when I get it cut out).
You guys rock my world!
J.

[UnklMickey]

hajamie said:

Ok, I think I've cracked it! ...

hajamie (or Hey Jamie, whatever the case might be.)

I'm not certain you've cracked it. I haven't looked at all 16 possibilities of switch position, to determine if they do exactly what you expect. One good proofreading technique is to remove all the cluttery bits like volume and tone controls, and phase switches that don't effect the switch logic. When I did this, I discovered either you were using more poles than you need for your s/p switch, or it's wired wrong. I'm quite certain the 2 circuits below function identically. Sadly, I don't have the time to go through all the possibilities, but if you find they all work for one, they will all work for the other.

If you are lucky, you won't have to use that "boring" switch for the s/p.
(unless you want to.)

Cheers,
Unk

chrisk said:

Is it correct to say "Ambitions are", or must I say "Ambition is"?

Well, I must say ambition is.

In the latter, it is a force (and may it be with you).

In the former, they are vectors, in multiple forceful directions.

I certainly hope that this clearly obfuscates the issue for you.

Yes Chris, I agree...

Vector is.


Did I really say that ?

[hajamie]

Hmm, that appears to do the same thing and is a bit simpler. Wow, I spent ages trying to make that (and failed)... Thanks!
I'll get back to you guys when I've built it! That could be some time off as I have to have the scratch plate cut first.
Laters,
J.

[UnklMickey]

Unk's rule #2, of switch simplification:

If 2 poles of a DPDT (on-on) are used,
...and a diagonal jumper is required
...and the other diagonal throws are open.

Then the diagonal jumper is the pole of a SPDT.

[JohnH]

Once it is boiled down to its essentials, it is indeed a simple circuit. I cant see any issues with it, other than that phase reverse action on mid, between series and parallel.

Now that the S/P switch is a two-pole, theres the option of adding another two poles to it (making into 4PDT), to make a phase re-reversing function on the middle. Then, the mid will stay in phase between series and para. You would then have DPDT's for the on/off switches, and a 4PDT for the S/p switch, plus assorted other phase switches.

John