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For the record, the Fender Treble Bbutt eXpander pot (TBX) is really two functions built into one dual element pot.

The first is a typical high frequency cut tone control from "5" to "0" on a Strat knob (the same effect over half of the rotational range).

The second is a gradual reduction in parallel load resistance from "5" to "10" on a Strat knob. This effect is similar to a gradual rather than quick no-load tone pot effect (which occurs from "9" to "10" on a no-load pot). It only reduces the pickup's load impedance somewhat.

It is a subtle expansion of the treble (harmonic) frequencies (up to the no-load point) rather than a bass-cut effect (which can only happen with a series capacitor or a parallel inductor.


Now, a clever sort would realize that, by using a true blend pot (not the mixer pan pots sold by virtually all guitar parts mongers) with one section effecting the parallel treble-cut tone function and the other effecting the resistance bypassed series output capacitor function, a real treble-cut/bass-cut tone function could be realized.

Note that these are only available in linear taper.

www.darrenriley.com/fenderparts.htm

Note that he calls them PAN pots (they are not). A PAN pot is comprised of a log and anti-log element (both are in linear piecewise approximation form) driven by the same shaft.

These are BLEND pots (both linear sections are FULLY ON [aka ZERO Ohms] in the center detent setting.

But, what do we expect from Fender and their whole 50 year long tremo'Leo/when it's a freakin' vibrato fiasco.


"AC Circuit Theory 101."

How many is "some" LEDs?

You will want to use high efficiency LEDs that are specified at 2 mA of current. Different colors may/will have different operating currents for similar levels of illumination.

If possible, you will want to put each group of three in series (to share the same operating current). This can usually be done from a 9 VDC battery. LEDs require a series current limiting resistor.

I would suggest that the LEDs be purchased from a competent company such as www.digikey.com that publish actual electrical specifications for their products.

What don't you like about it?

Why don't you tune it with a $0.10 cap?

Pickup Coil Response Tuning

Well, I'm really glad that you didn't say that your pickups had outputs of 10K29 Ohms and 9K1 Ohms.

The DC resistance of a pickup is the output impedance (the internal impediment to the output signal) at DC when it is producing no output signal.

Rating a pickup's output by its DC resistance is akin to rating a person's intelligence by their shoe size.

I don't remember anymore but I think that it was Photoshop or Illustrator.

It was a professional presentation package. While producing pretty results, it generally is not of meaningful use in schematic iteration.


Send him a PM and ask.

Who made them? What model are they?



I presume that you meant K Ohms. How can it read 9K1 to 13K Ohms? Does the reading wiggle around? What meter are you using? Is the battery any good? Are the leads intermittent?



10K29 Ohms is well within the normal manufacturing tolerance of a nominal 10K5 Ohm pickup model.

9K1 Ohms is well within the normal manufacturing tolerance of a nominal 9K5 Ohm pickup model (without the wiggling).

Aha, so you're the guy that owns the stock in the Tele 4-way switch company!

The only issue that I have with this is the shorting of pickups (generators that derive their output from harvesting the vibrating energy of the strings). The more that you load a generator (driving its internal impedance through an external short as a load), the more energy is harvested. This directly reduces sustain and harmonic content.

No one has posted meaningful data as to the effect of this.

Your diagram still is incomplete. Perhaps if you posted a logical description of what you think that it does that would be of help.



I have an excellent understanding of electronic system design, likely from spending 30+ years as an electrical engineer designing embedded analog and microprocessor control systems and having a number of patents issued and pending.

I understand and design fairly complex wiring schemes for guitars;

The HSS All Mode 'Caster 20070808

The PRS RotoBucker


My point is that while I've mentioned several flaws with your "plumbing", your solution is just to remove connections without understanding why or where they should go.

I don't create new wiring designs by simply modifying existing ones that other's have done (usually), but by starting with specifications (what it's supposed to do) and implementing from there. This is fairly simple and straightforward.


Once you can quantify what this design is supposed to do electrically (please leave out all the Tele twang, Strat quack, Brian May, and metal metaphors as they are meaningless from a logical switching perspective), I will be more than willing to help.

However, I will not take the time to trace your plumbing into a schematic and then try to figure out what it actually does and what you might think/hope that it does.


Wiring design is a logical process. It starts with specifications. When one embarks on a trip, it helps to have a destination in mind.


hint
This module could form the basis for each pickup as well as both pickups in series and parallel as it is a DPDT switch and a true blend pot.
Series_Parallel Blend Pot w/ DPDT switch

These modules offer alternative ways of doing blended series/parallel;
Fun with switches, take 1 sections "D" and "F".
/hint


If your intent is to arrive at a functional design, do let me know. I will require that you figure out things and understand how things work. I will not just do everything for you.

Yep!


You betcha!

The right pole on the DPDT is selecting between the middle (+) output (in the series mode) and the selected pickups from the lever switch (in the parallel mode). This selection goes to the volume pot hot (and it's the only thing that goes to the volume pot hot).



That's why I just don't tell you what wires to move. I'd much rather that you "see" in order to enable other's to also see.


While you're at it, jumper the back shells of all three pots together; this will give redundant shield connections.

There are those a'web that will call these connections "ground loops", (they are not) but these folks struggle mightily to discern the difference between a burro and a burrow.

The left half of the DPDT switch S2 matches the wiring in RH's design.

The right half is not even close. Check your drawing against his.

This design requires the manipulation of up to 3 switches to change modes; there are several simpler, more featured designs available.

The drawing shows the 0.0022 uF cap/220K resistor going from the volume pot out to guitar ground. This is not how the treble preservation circuit works. This will shunt the highest frequencies to ground.

It should go from the volume pot hot in to the volume pot out.


The neck pickup has the black signal wire connected to guitar ground. Therefore, phase reversal is not possible as wired.


The SPDT switch proposed for inter-pickup series/parallel does not do this. When the switch connects the neck red wire to guitar ground, it shorts out the neck south coil. In its other position, it connects the neck south coil in parallel with whatever is selected for the bridge. This is not inter-pickup series/parallel.


All three blend/pan pots have guitar ground connections thus preventing an inter-pickup series structure.


It's possible that there will be 7 pots in parallel (both sections of three blend/pan pots and the volume pot) as well as the tone circuit.

On even the brightest days this will be a very dark sounding guitar.


Following your wiring diagram is giving me an aneurysm. Wiring diagrams are situational instantiations which obfuscate the architectural detail. Please design from a schematic view. Once you "see" things from this perspective, the modular nature of the design will become obvious as well as the module interactions.

The wiring instantiation can be "poured" when the architecture is complete.

You're trying to build a house from the inside out without any view as to what the house really looks like overall.

The pivot points are the beveled edge of the mounting screw holes and the shanks of the screws (those farthest from the neck until all equally wear in). If the pivot point was between the bridge plate and the guitar body, the bridge screw pivot points would slide up and down the mounting screw shanks.

Here's a link as to why Fender factory vibrato (tremo'Leo) bridges are generally junk.

www.callahamguitars.com/bridges.htm



These screws are screwed into the body. Torque is meaningless. The vibrato bridge plate must be free to tilt at least downward (detune only) or the vibrato will not be functional.

If the vibrato plate is flush against the body, it will not be able to up tune (raise frequencies) and will cause the bridge plate to move up and down the screw shanks as it is operated.

Since the underside of the mounting screw heads are flat (perpendicular to the shank), a "happy medium" point must be found such that the pivot points are somewhat further down the shanks than directly under the screw heads. This is why the mounting screws must be backed out enough to prevent the pivot points from siding up and down the shanks.


Also note that Callaham indicates that the vintage 6 screw vibrato (he thinks that it's a tremo'Leo also) is only usable in the detune mode. I tend to agree, and generally only use them in a blocked vibrato mode ( a "fixed" bridge with the built-in reverb springs).

Remember, a Strat is really an inside-out semi-acoustic guitar.

It's not the "output" to the output transformer, but the load presented to the output stage of the amp that is of most concern. In this case, twice the rated load would be presented to the output stage. Also, the output winding on the output transformer is a tapped winding and you would exceed the ratings of the wire gauge used as well as the power rating of the core.

You will overload/overheat the output transformer as well as overload the output stage.

From a theoretical basis, presenting half the load (twice the impedance) to each tap may present the proper load to the output stage and transformer, but I'd wait for sumgai to give his opinion as empirical data is.

A presumption would be that the Hot Rails and the JB have identical wiring which may not be true since the SD diagram is for two mini-humbuckers (single coil sized) and a single coil.

However, our Pickup Wire Colors and Polarity post indicates only one wiring scheme for SD 4-wire humbuckers.

Based on this, I would presume that they are wired the same.

The diagram indicates that the slug (north polarity) coil is selected in the bridge plus middle position. I don't see any indication of the standard polarity of SD single coil pickups on their web site, nor am I willing to spend time "fishing" for this information.

A simple test is to briefly place the middle pickup's top pole pieces against the bridge slug coil pole pieces.

If they attract, they are RP with respect to each other and phasing is a simple exercise of swapping the middle pickup wires with each other if needed.

If they repel, then they are not RP with respect to each other and polarity and phasing are then somewhat more complex exercises. If you are willing to use the screw (south) coil on the bridge humbucker, disconnect the wire from the 5-way lever switch that goes to the back of the volume pot and connect it to the hot terminal on the volume pot. This will select the south coils on both the bridge and neck in conjunction with the middle.

You may still need to do the exercise of swapping the middle pickup wires with each other if the combined sound is weak and thin.