2 Humbucker Setup (Sg or Les Paul)

[suicufnoc]

Just drew this up today. I don't have a guitar to try it on yet, though. It has two coil taps, but on opposite sides of each pickup, so when both taps are activated, it's humbucking.
Edit: The solo switch now bypasses the coil tap.

[UnklMickey]

Hi suicufnoc,

Welcome to Guitarnuts2.

Most people start here with problems or questions. Your first post brings a finished diagram. That's a nice change of pace. I haven't had the time to look over your drawing carefully, but I hope to have the time to do that soon. The drawing itself looks very clean. What program did you use to draw it?

Linking to ImageShack is a bit clumsy. You can display your pictures directly if you like. Over 800 pixels wide gives some of us problems, but your drawing is less than that. To display directly, You can use image tags around the address like this:

[img src="http://img441.imageshack.us/img441/4073/diagram2pe1.png"]

Having a common hot and separate grounds for the stereo signals seems like it might be a problem. I'll let you know my opinion, after I look more carefully at your circuit.

Ancient Chinese proverb says: Having an open circuit in the kill position will make it more prone to hum. If at all possible, you should make the kill position a short, instead.

I'm not sure when I'll be back, but I'm sure others will weigh in on this, too.


Cheers,

Unk

[suicufnoc]

Thanks for the input. I don't think it's possible to make the killswitch short without using a seperate switch. It might be with a 4pdt center on, but I haven't been able to find one that would work in a guitar. Or I could use a relay, but then I would need a battery. Relays might interfere with the pickups, too.
Maybe I'll just drop the solo position.

As for the split grounds, I don't think it would be a problem. As long as both grounds are completely seperate(I'm pretty sure they are) The advantage is that when you plug in a mono cord, the grounds are shorted, making the guitar work normally. Disadvange: It takes either a custom cord or adapter/ switchbox to use the stereo.
Edit: I drew it in paint

[sumgai]

Ancient One,

Welcome to the NutzHouse! ;D

Nice diagram. However, like the Unk said, someone else will chime in soon enough. That would be me.

Overall, this scheme will work, with one proviso: You absolutely must use separatly grounded amplifiers. If they share a common ground anywhere along the signal path,, the separation disappears. Even commonly grounded power supplies present a clear danger to your intent, they may bollix up the works as well.

If you're really careful in that regard, then I think you've got a winner. ;D

To expand on Unk's statement about the Kill portion of your Solo switch........ May I suggest that you use a 4P3T (on/on/on) switch instead, as found here:
Templates? Check the first post, top center diagram, it'll show you the way the contacts are arranged in the center position. That'll short the amplifier's input when in Kill mode, which means a lot less noise and such.

HTH


sumgai

[UnklMickey]

sumgai said:

...You absolutely must use separately grounded amplifiers. If they share a common ground anywhere along the signal path,, the separation disappears. Even commonly grounded power supplies present a clear danger to your intent, they may will bollix up the works as well...

I've taken the liberty of editing the quote I cite you on, Chief.

Anywhere the ground is common will spoil the soup. Even if the signal goes to two separate amplifiers, if they are both grounded through the mains supply the signal becomes common to both. Although it seemed a novel idea, this one will likely be a non-starter. Having a more conventional stereo arrangement with two signal conductors and one ground will be the only way to go. This means a switch of some sort to change from stereo to mono.

suicufnoc,

I'm impressed with that drawing. It's the nicest I've ever seen created with paint. You sir, have some mad drawing skills.

[sumgai]

unk,

unklmickey said:

sumgai said:

...You absolutely must use separately grounded amplifiers. If they share a common ground anywhere along the signal path,, the separation disappears. Even commonly grounded power supplies present a clear danger to your intent, they may will bollix up the works as well...

I've taken the liberty of editing the quote I cite you on, Chief.

Anywhere the ground is common will spoil the soup. Even if the signal goes to two separate amplifiers, if they are both grounded through the mains supply the signal becomes common to both. Although it seemed a novel idea, this one will likely be a non-starter. Having a more conventional stereo arrangement with two signal conductors and one ground will be the only way to go. This means a switch of some sort to change from stereo to mono.

I chose "may" because where the amp for each channel is being powered by an isolation transformer (like them there wall-wart thingies, only... bigger), then it's likely the signals will remain separated. Not that I guarantee that result, of course, I'm just supposing the likelyhood here, tha's all.

I'd rather see the whole thing inverted back to normal phasing (split signals, common ground), but I can appreciate the desire to not incorporate any extra jacks or switches...... it's all about being stealthy, eh?


sumgai

[suicufnoc]

sumgai: yeah...
Unk: thanks

I think I'll have to drop the stereo though, because I'm doing this to a guitar i'm going to be renting out, and I don't wan't people to freak out when they see it:)
The kill/solo switch might not get put on either, at least not for a while. I'm not sure where to put it(gibson sg special, new style pickguard) I wan't the hole to be under the pickguard, but higher up than the pickguard reaches. Plus I don't want to lose resale value. The pulls are going on right away, though:)

I'm all for using a 4p3t(shouldn't it be called a 4pdt, thought, even though it has the center position?), if anyone knows where to get one under $20 with a big enough toggle, but small enough to fit inside a thin guitar(sg)

(oh, if anyones wondering about the really wierd ground wiring, other thanthe stereo setup, it's to keep the ground loop as short as possible when bypassing the pickup. Never thought about that before, but technically...)

[suicufnoc]

Okay, I changed it to an on-on-on switch. Really all it would take is 2 poles of on-on-on, and one extra pole of either on-on-on or on-off-on(I'm only using three poles, to be short:))

[sumgai]

Tao Master,

I think I'll have to drop the stereo though, because I'm doing this to a guitar i'm going to be renting out, and I don't wan't people to freak out when they see it:)

Rent? You rent out your guitar? Why, I've never heard of such a thing.

BTW, how much does one get for renting out his axe?

The kill/solo switch might not get put on either, at least not for a while. I'm not sure where to put it(gibson sg special, new style pickguard) I wan't the hole to be under the pickguard, but higher up than the pickguard reaches. Plus I don't want to lose resale value.

Many moons ago, I saw a strange Gibby that had no output jack! The owner was faced with the same dilemma as you, wanting to maintain the resale value. So he bought a second back cover plate for the cavity, drilled a hole for the output jack therein (after all, he was already using a right-angle cable anyways.....), and used the jack's former hole for a toggle switch. He still had it when last I saw him, but it's easy to see how he could reverse everything and be back at Square One in a jiffy, giving him maximum resale value.

I'm all for using a 4p3t(shouldn't it be called a 4pdt, thought, even though it has the center position?)

Technically speaking, when the term 'throw' was first used, it meant 'position' - you could throw the switch into one of two positions. Imagine a big knife switch, ala the mad-scientist labratories like in the old Frankenstein movies, and you've got it. Many of us still stick with that definition, although it's a given that no marketer (sales person) has ever attended so much as a basic electricty class in school, so when they see that a switch can move from one end to the other of it's travel, they just figure there must be two positions, and call it a DoubleThrow. For them, the center positioin is an accident. One has to wonder how they manage to tie their shoelaces in the morning........

For this reason, you will see many catalogs (and other descriptions) incorrectly identify the number of throws. Don't let it throw you off (sorry! ), let the secondary descriptor be your guide - on/off/on, and such like that.

In fact, whenever you're in doubt, refer back to the Templates thread, and you'll be at homebase, with all the correct terminology. ;D

...... if anyone knows where to get one under $20 with a big enough toggle, but small enough to fit inside a thin guitar(sg)

Gotta send you to another link for this one: Parts, and where to get 'em!
Scroll down to the appropriate section on Part Suppliers, I'm sure you'll find someone in there who will take your 20 washers for a measly switch.

Last, but not least:

(oh, if anyones wondering about the really wierd ground wiring, other thanthe stereo setup, it's to keep the ground loop as short as possible when bypassing the pickup. Never thought about that before, but technically...)

Well, again technically speaking, a schematic such as you've drawn should not attempt to replicate anything from the real world application. Unless there are extenuating circumstances, such as for safety reasons in areas of High Voltage, you don't ordinarily try to show how wires are routed. Your diagram would be much clearer (we'd make sense of it more quickly) if you were to clean up the umpty-squat number of ground wires running all over the place.

And the ultimate goal, not always achievable, but nonetheless desirable, is to have no ground loops at all. If you are putting one in on purpose, I'd like to hear your explanation for it, please.

One more request....... why is it that you don't want the Neck to be coil-tappable unless the Bridge is already coil-tapped? Isn't that kind of artificially limiting the number of potential tonal combinations? Just wonderin' here............


sumgai

[suicufnoc]

Generally anywhere from $50-150 a night But you have to rent out drums, guitars, stands, bass amps...

The grounds were drawn in for the sake of the stereo setup, i'll remove them soon.
As far as ground loops, when you bypass a pickup, your ground is both running through the pickup, and through the bypass switch. Not a big deal at all, but...

The idea with the coil taps is to only flip one switch, and have both Pups tapped.

[sumgai]

unconfused,

As far as ground loops, when you bypass a pickup, your ground is both running through the pickup, and through the bypass switch. Not a big deal at all, but...

That's what we call shunting, and you're correct, it is a path of redundancy. However, the micro currents generated within the pickup's coil (from another coil in the string) will be swamped by the currents generated from the vibrating strings directly overhead. If the pup is shunted out of the circuit, there is a chance that some deleterious effect may be noticed, but JohnH has done a study on this, and concluded that for the most part, there's no harm done. John's thread: Beware the Tone Sucker!

HTH


sumgai

[suicufnoc]

Fixed some stuff. I also found the perfect switch, dimarzio sells one. $30 though... Next time.