Need help with guitar electronics

[Jos Hoogervorst]

Dear fellow musicians!


First of all I'd like to make clear that English isn't my first language (it's Dutch), so hopefully I can make myself understandable!

This is the case:

I'm building an electric guitar as my final assignment to become a carpenter with a diploma (yeah I know... it's a little weird indeed, but why not make one if you're a guitarist anyway)
As I am a quite a rookie on building guitars, I could use some help when it comes to the electronics.
I know what results I'm looking for, but I've got no clue how to work it out yet.

I allready bought 2 Duesenberg D-Tron PU's (Bridge, Neck - Nickel)
The other components are yet to be bought.

This is more or less what I am trying to build:

Push/Pull Potmeter #1: Volume overall (so both PU's)

Down: PU's parallel (this is pretty much the standard way, right?)
Up: PU's in series

P/P #2 and #3 respectively: Tone

Down: Hum bucker (so no change)
Up: 'Tuned Coil Tap'
(I read this in a book: a tuned coil tap gives the ability to turn a Hum bucker PU to single coil with the ability to use additional 'low' from the other PU in a hum bucker. The reason for this is that - by coil tapping a hum bucker - the resulting single coil will, apparently, miss the low frequencies a regular single coil PU provides. By manually controlling the high frequencies that need to be blocked out from the other pickup with a temporary pot meter, one is able to detect the desired tone. Then, one can measure the resistance of this setup, and replace the pot meter for a resistance (or is it a capacitor?) element.

3-Way switch (just standard LP):

Up: Neck PU on
Mid: Both on
Down Bridge PU on

For me, all of this still sounds equally difficult to understand as doing a masters degree in rocket science, but hopefully one of you has got a huge grey mass

Thanks in advance, if you have additional questions, I'll be more than please to provide the answers!


Kind regards,


Jos Hoogervorst
hoogervorst@live.nl (Not sure whether I'm allowed to give my mail address, but I don't mind it myself though)

[Greg Robinson]

Hi Jos,

First off, I've hidden your email address, this is to prevent web crawlers from harvesting it.

Which book did you read about this "tuned coil tap"? I believe that it would actually be a "tuned coil cut", these terms are often confused or used incorrectly. I don't remember the last time I saw a pickup with coil taps, but I see people referring to coil cutting as "coil-tapping" all the time.
Also, I think you might be confusing the likely function - it would be impossible to add just the bass frequencies from one coil to another without rolling the highs off both in a passive system, but you could quite simply add a high pass filter to one coil. I've experimented with this before, and whilst maybe a slightly novel effect, I don't think it's particularly practical.

In regards the series/parallel switching push/pull pot, this can be made to "kind-of" work, but will disable the function of the three way toggle, unless you can find a push/pull pot with more than dpdt.

[Jos Hoogervorst]

Hey Greg!

Thanks for your reply man, I got this from a book named 'Make Your Own Electric Guitar Bass' by Dennis Waring and David Raymond. I could have mistaken the word 'cut' for 'tap', but I'm not really sure about that though. The thing is, I borrowed the book from my schools library, but it's been rented out to someone else at the moment.
Maybe I misunderstood the way these 'tuned coil taps', or whatever they're called, are meant to just reduce the output of one of the coils. I will look that up again in the book whenever I'll have the opportunity.

I'd rather had my problems solved than getting to know that it won't work like this But I'm still glad you told me obviously, so thanks for that!

Have you heard about the thing the authors said about coils from a HB having a 'thinner' sound than a regular single coil? And if so: do you know of any methods to get the sound as close as possible to the original single coils when 'cutting' a HB?

I don't really care about how I should get the desired results, I just want to keep 3 pot meters and whatever amount of switches, as I've already computer routed my guitar body...
If you know of a different method to get the wished results, I'd be really happy.

And if not, I'm really thankful for your info man!


Cheers!


Jos

[Greg Robinson]

Ok, well in my opinion you should reconsider what your aims are. I'll detail why.

You've suggested a volume, tone, tone configuration for your three pots, I'd recommend volume, volume, tone instead. This is because when both pickups are engaged (pickup selector in middle position), both tone controls will act like a master tone, they will not act on the individual pickups. If you had independent volume controls, you could have some degree of independent tone control, but only when the volume controls are turned down a bit: adding series resistance and some degree of isolation. In practice though, the two tone controls are in parallel and will therefore not act independently, making the second one redundant. Volume controls on the other hand can easily be made independent, so that would be much more functional.

The difference in tone between a coil cut humbucker and a genuine single coil depends largely on the individual pickup, but yes, they often lack the "body" or "richness" of a traditional Strat type single coil. Normally one would just accept the tone of a split humbucker, as it is still a lot more "Strat" than a humbucker, and in my experience there aren't too many good tricks for making it sound more like one. Results will vary widely with different pickup designs too.
I'd recommend just sticking with a plain-Jane coil cut.

The idea of a series/parallel switch for the middle position seems novel at first, but rarely does the series option sound any good with humbuckers. It's great with single coils - I mod a lot of Telecasters with this option (4 way switch), but is just a dark farting mess with every pair of humbuckers I've tried it with.
Also, if you want to keep the switching intuitive (which I always highly recommend - nothing worse than trying to command the space shuttle when it has as little labeling as guitars normally do), it's tricky to get it to all work as expected in each switch position, unless you can find switches with enough extra poles.


So, what I would suggest would be:
Three way toggle switch for pickup selection
Neck volume with coil cut on push-pull
Bridge volume with coil cut on push-pull
Master tone


If you're dead set on having a third push-pull function, I might suggest a phase/polarity switch, this would give you another sound entirely - very nasal, great for certain overdriven tones.


Anyway, just my thoughts and opinions, let us know if you're getting a clearer idea of what you want planned out, and we can start directing you towards getting a circuit worked out.

[Jos Hoogervorst]

My god...

Clearly, I most definitely need a speed course on guitar electronics!

I think I'll just put a midi PU attached to an internal iPhone on my guitar Haha, or maybe I'll just put a chaos pad in there like the 'muse'icians

But enough of that. I didn't even know you can't have a working overall volume with 2 tone pods on a guitar.
Thanks for the help man, I'm gonna look for a local guy who's willing to give me a speed course on this.

Apart from this, I'm glad I've got a working set-up now, as you just gave me one.

Could I maybe ask you one more question?

My former internship boss (he's a professional upright bass builder/repairman) told me I might look into the idea of putting an additional single coil (just the cheapest one I can get) into the guitar body (out of sight) in order to cancel the hum when using the 'single coils' on my guitar...

What's your opinion on this?

Thanks once more man!


Jos

[Greg Robinson]

Hi Jos,

Sorry, I might have confused you:

I didn't even know you can't have a working overall volume with 2 tone pods on a guitar.

You can have a master volume if you have two tone controls. What you can't have are two independent tone controls in a passive system. That's why I suggested two volume controls - since you seem locked into the three control format.

My former internship boss (he's a professional upright bass builder/repairman) told me I might look into the idea of putting an additional single coil (just the cheapest one I can get) into the guitar body (out of sight) in order to cancel the hum when using the 'single coils' on my guitar...

This will add some degree of hum cancelling (if the phasing and orientation are good), but it will be pretty poor as the coils won't be matched. Also, in a passive system it will effect the frequency response of the pickup it's connected to - this usually will make it sound less like a Strat style single coil than just a split humbucker on its own.
If you get into active electronic trickery, it can be made to be quite effective - but I think that would be putting the cart before the horse at this stage.

[Jos Hoogervorst]

I just had a response from a Dutch guitar building centre I sent an e-mail just before I entered this forum.

Freely translated this is their answer to (pretty much) the same question:

All of this should be possible, except for one thing: You cannot switch both PU's series/parallel with only one (P/P) pot meter. You need 2 for that.
Tuned coil taps are a good idea, as you said: it will result in a warmer kind of single coil than without it.
Kind regards, etc...

I'm not sure whether this 'tuned coil tap' (against better knowledge) is a common dutch/english term to address such a setup, but it seems these guys are either lazy, not reliable or actually have knowledge we both don't have. In any case: if last statement is true (I'd be glad, but honestly I trust your opinion a little more as you're not payed to reply to my questions) I'll try to find this out unto the bottom and will tell you about my findings.

I can see why this additional single coil to cancel out hum will only work when it's an exact same single coil. I'll leave that out then.

What do you mean by 'passive' system..., you mean that I'm using passive PU's? (This is the case)

Thanks for your help AGAIN

If you're sort of through with answering me, I wouldn't blame you!

Cheers

[Rodger Knox]

Passive means there's no powered circuitry, so no manipulation of the signal other than eliminating parts of it(Tone control removes high frequencies). Active electronics are powered, (usually by a 9V battery) which means a preamp with controls.

[Greg Robinson]

Hi Jos,

Hmmm, not sure if "tuned coil tap" is lost in translation or not. There are ways to partially combine the signals from two coils, just in my experience they've never really sounded much more "single-coil-like" than just a split humbucker by itself, and it does add a fair bit more complexity to the wiring.

Humbucker coils usually have lower inductance than single coils, this is probably the biggest single factor in the difference in tone between a split humbucker and a true single coil. This results in less bass frequency response (and lower output). Trying to add more bass frequencies from the other coil would require an inductor in series with the second coil (low pass filter - coils in parallel), but inductors are generally quite sensitive to noise pickup, and will add their own resonant peaks, which may be undesirable (inductors are the least "ideal" of electronic components). The parasitic capacitance may also roll off excess highs (depends on the specs of the inductor), which may also move the tone further away from good single coil tone.

The other way to partially combine the two coils would be to run one through a cap to add just high frequencies (high pass filter), but this does not sound at all like you are describing.

I can see why this additional single coil to cancel out hum will only work when it's an exact same single coil. I'll leave that out then.

It will still cancel some noise, it will just be far from ideal. In some cases it can actually INCREASE noise pickup, at least for some frequencies, but this is more of an intellectual concern.

All of this should be possible, except for one thing: You cannot switch both PU's series/parallel with only one (P/P) pot meter. You need 2 for that.

Reading this, I'm not sure if they, or I, misunderstood your intention.
I read your original post to mean that you wanted to have a switch to change the middle pickup selector option (both pickups) from the two pickups in parallel, to both pickups in series.
The way I've read the response you received, it seems they read it as you wanting to be able to change switch the individual humbuckers from series (normal humbucker wiring), to parallel (lower output, less high frequencies, still hum cancelling).
I'd like to clarify what your original intention was, just to make sure we're on the same page, although it might be a moot point, as their assessment is correct either way (as I have stated above).

What do you mean by 'passive' system..., you mean that I'm using passive PU's? (This is the case)

Yes, a passive system contains no "active" components that require a power source like a battery. Active systems allow a lot more flexibility, but the complexity goes up accordingly.

Don't worry, I'll be sticking around to help out. Hopefully I'll be able to help you draw up your wiring scheme yourself - so that you better understand it. It's not as complex as it first appears, you'll be able to do it!

[Beate Ritzert]

First of all (in German) a large collection of passive bass circuitries showing many of the possibilities discussed earlier. http://161589.homepagemodules.de/t29f2- ... aesse.html

Secondly: Your pickups do not seem to be splittable. Just one single shielded wire. That more or less excludes most of the tricks You have discussed. So my advice: KISS - keep it smart and simple: toggle switch, volume, tone. That's it. If You want to have more possibilities, add a (R-) C-Switch which modifies the resonance peak of Your PUs and maybe a varitone switch. That is a passive notch filter damping a certain part of the audible spectrum, typically in the lower midths. These switches can be used either in Push-Pull pots or with rotary switches. The latter will give You more possibilities.

Have fun

Beate

[Greg Robinson]

Beate, I just looked the pickups up, they're advertised as having 4 conductor leads, and photos also appear to bear this out.

[Beate Ritzert]

Thanks for the info. The page of the German distributor pointed me in the wrong direction.

Anyway: if i built a guitar with these PUs i would keep it simple - toggle, volume, possibly with treble bleed capacitor and an RC-switch 4 positions. Regarding the present background knowledge of Jos i would suggest either to extend it or to keep the guitar even simpler: toggle, volume, simple tone control.