Strat - two tone controls - not actually per pickup?

danox574

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Background: Do not play much guitar, I built a Gecko 6, but laying out electronics for a stratocaster section of a multi-neck guitar project. That's a bit TMI, I am just studying the stratocaster wiring at this time. I am doing this without a stratocaster on hand and only knowledge of some bass wiring and good understanding of schematics in other areas of electronics.

I am studying the standard modern stratocaster 3pu wiring diagrams, as in the stock configuration with the 5 way switch and two tone controls.

Each time I read about how these work, I hear them described as a 'Middle pickup tone control' and a 'Neck pickup tone control'. The bridge is without tone control, and I know that it is also wired in in some guitars, but for the purposes of this discussion - let's go with the traditional no tone control for bridge wiring, with a sample wiring diagram borrowed from StewMac here: http://www.stewmac.com/freeinfo/i-2001/2001.gif

However, I can't figure out why these would be consider pickup specific tone controls based on that diagram. On the left side of the 5 way switch, any pickups selected are connected in parallel to the common pin. In other words - they are mixed together before they get to the tone controls.

On the right side of the 5 way switch (isolated from the left side until the wire is run from common to common as shown in the diagram), one or more tone controls are put in parallel with the mixed pickup output depending on the position. In position 1 (bridge), no tone controls are connected to the output line. In position 2, and 3 the bottom tone control (Fender calls it T2) is bridged in an active. In position 4, both T1 and T2 are active, and in position 5, only T1 is active.

So, I understand that these tone controls are 'active' when certain pickups are selected, but in no way that I can see are these tone controls function only for the output from a certain pickup as the pickups output lines are bridged together on the other side of the switch before they get to the tone controls.

Since these tone pots simply decide how much of the signal is bridged to ground through a .047uF cap (in the sample schematic I provided above), they actually do the same thing as each other (in fact, they share a single cap). Having two tone controls, switched in and out as the pickups are added and removed, sounds like a nice tone preset system for each position of the 5 way switch that includes T1, T1&T2, or T2 in the circuit.

However - if any selected pickups are mixed before they even get to the other side of the 5 way switch - how can this achieve anything that a single pot and cap cannot?  It looks like the resistance from the two tone controls is just in series when T1&T2 are both in the circuit (position 4), so maybe the total resistance is 500K at max instead of the typical 250K pot itself.  Other than that - I can't see a functional difference over a single tone control.

Yet, the number of people I see claiming that these tone pots affect each pickup individually has caused me to come here and try to find out what I am missing.  Claiming that a single tone control reduces the overall palette of sounds.  Or is it that folks just 'feel' that T1 and T2 are bound to certain pickups signals because they switch in and out when the pickups are switched in and out?
 
When I built my strat, I just made a master volume and master tone control with the third hole used as a mini toggle to split the humbucker in the bridge position.  I love the sounds I get from it.

If I had 3 single coils, I would have thought about putting in an unattached pot with a knob, as a dummy control. Then I would have a backup pot on hand in case I'm on the road and one of the other pots goes awry.
 
The answer is a fairly simple one. When Strat wiring was developed it was a 3 way switch, so the tone controls would be separate as there was technically no in between position, although you could sort of wedge the switch in between.

 
It is astounding to realize just how many people are not properly educated on how a guitar's controls actually work. People think that tone controls are independent of each other, but as you have just figured out, that is not the case. This is one of the many misunderstandings that are common in guitarland.
 
stratamania said:
The answer is a fairly simple one. When Strat wiring was developed it was a 3 way switch, so the tone controls would be separate as there was technically no in between position, although you could sort of wedge the switch in between.

In that case, they did function per pickup, but ultimately each one was a preset for the switch position that affected them.  Although I was aware of the notch positions being a later (70s) enhancement from the factory, it never occurred to me to think about the dual tones in that early context.  Good one.

line6man said:
It is astounding to realize just how many people are not properly educated on how a guitar's controls actually work. People think that tone controls are independent of each other, but as you have just figured out, that is not the case. This is one of the many misunderstandings that are common in guitarland.

Some of it seems to be the fault of it being very device/wiring driven instead of an actual schematic.  I have designed circuits, CAD PCB layouts and had them manufactured for my projects, etc. and the way that guitar wiring is presented is very alien to me.  Finding a schematic for a guitar is much harder than a picture of point to point wiring.  Thanks for confirming.

I'm trying to overlay passive guitar and bass electronics with common controls and handling all switching from a single DPDT at most (so I can use a push-pull pot for instrument selection) and keep the whole thing looking minimal and not cluttering it up with any unnecessary controls. Traditional P-Bass electronics absolutely match a single tone control stratocaster, so if I'm willing to move to single tone (and I'm having trouble deciding why I wouldn't after you confirmed) it's going to be easier than I thought...maybe I could even put a PJ on the bass side and still meet my requirements.

Thanks again everyone!
 
danox574 said:
... the way that guitar wiring is presented is very alien to me.  Finding a schematic for a guitar is much harder than a picture of point to point wiring.  Thanks for confirming.

You're not alone. Guitar wiring diagrams drive me nuts. Give me a schematic, or tell me what it's supposed to do and I'll draw one myself.
 
Cagey said:
danox574 said:
... the way that guitar wiring is presented is very alien to me.  Finding a schematic for a guitar is much harder than a picture of point to point wiring.  Thanks for confirming.

You're not alone. Guitar wiring diagrams drive me nuts. Give me a schematic, or tell me what it's supposed to do and I'll draw one myself.

Ditto!  I hate those things!  A schematic I can understand.  Wiring diagrams drive me crazy.

Let's all start a grumpy schematic club! "... back in my day all we had was schematics sonny!"
 
The vast majority of people that are trying to wire guitars simply do not know how to read or understand schematics, and hence, there is a need for "paint by numbers" diagrams. They serve a purpose, and there is nothing wrong with them.

I think that the most frequent problem with diagrams, however, is the fact that there can be 50 different ways to physically configure the components for the same electrical behavior, and so there will be many different diagrams of the same wiring scheme. I've seen a lot of people get confused about things like tone control wiring. Sometimes the capacitor goes to ground, and sometimes it goes to the signal path, and sometimes it's soldered to the back of the tone pot, and sometimes it's soldered to the back of another pot, and so on. Electrically, it is all the same.
 
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