A word on Internet Wisdom

Internet wisdom isn't always wise. I made a mistake and turned off my brain while creating my initial wiring diagram. Don't get me wrong, my diagram works perfectly, but my hopes for what it would provide were somewhat ill founded.

The "250k" for single coil and "500k" for humbucker internet wisdom is missing context. The best way to think of a passive guitar circuit is an alternating current source (the pickups), a voltage divider for volume (volume control) and frequency roll off (tone controls). The choice of resistance for the potentiometers only really matters for tone controls, as careful selection of capacitor and potentiometer define cutoff frequency and range. However, since my circuit has no tone controls, the resistance value for the volume is largely inconsequential.  

It has been many years since engineering school, but that is no excuse... Just be careful about turning off your brain. 

Initial Wiring Diagram

The plan for this guitar is to experiment with a few things, one of which is a wiring setup that isn't too crazy in its final form (may be crazy in intermediate steps) but can handle the tones that I want. This initial wiring diagram is intended to play with a few things, specifically, coil tapping and playing around with resistor values for the volume control. This particular wiring diagram contains no tone circuit, as I find I never use the tone knobs on any of my guitars. The mini switches and the five-way super switch are from AllParts. The volume pot is the 500k volume pot that was already in the guitar. The jack is the standard jack that came with the guitar.

With this setup, other than parallel wired single humbuckers, you can pretty much get all of the options that may end up being interesting to me. My goal was to get a few standard-ish tones:

• Strat neck tone: five-way switch in position 5, switch two in 'up' position
• 335 style neck tone: five-way switch in position 5, switch two in 'down' position
• Telecaster 'twang': five-way switch in positon 3, switch two in 'up' position
• SRV Strat-ish; five-way switch in position 4, switch two in 'down' position
• Mark Knopfler/Sultans of Swing: five-way siwtch in positon 2, switch two in 'down' position

The first switch (the resistor bypass) is based on 'internet wisdom' that you use 250k pots for single coil pickups and 500k pots for humbucker pickups. The switch enables/disables a parallel 500k ohm resistor to create an effective 250k ohm resistor. 

The little things are the hardest

I'm trying to turn my wiring diagrams into things like PDF files (so I can share them). It turns out, this is a real pain in the ass. The flow chart/diagraming software like Visio would be perfect, but I don't have it. Learning Illustrator or InDesign in order to do such a simple diagram is proving to be extremely frustrating.

Test fitting the pick guard

After drilling the holes for the neck pickup screws length, I test fit the pick guard. Only a couple of the holes line up. Bummer. I'll have to drill some new ones. Luckily none of the existing holes will be exposed. I don't care about the appearance too much right now, but I don't want it to be horrible if I can help it.

Preparing the Pickguard

I've mounted the pickups, five-way switch and two mini switches to the new pick guard.

There is a slight problem with the five way switch and the pick guard. The one and five position don't fully complete the connection. I'll have to file down the lever slot to ensure the switch can perform its full travel.

The shielding is quite evident. The volume control is not yet mounted on the pick guard.

Another problem has showed up. Since the Squire Strat is as cheaply produced as possible, the neck pickup position was routed for a humbucker (which is great), but there is no route for the long, spring loaded mounting screws. The picture below is of the body, the bridge pickup route contains two deep channels that are not visible on the neck pickup route.

 

Here is the long screw holding the pickup to the pick guard.

I ended up using an electric drill instead of a router to make the holes for the screws to fit. A simple enough solution.

Wiring it up should be straight forward. 

Positioning the Pickups

One thing the ES-335 style guitar and the Fender Stratocaster have in common with the neck pickup is the placement along the scale length. On the Strat, the neck pickup is placed at the 24th fret position, or specifically, one fourth of the scale length. On an ES-335 style guitar, the screw lug of the humbucker is placed at the 24th fret position.

Since my project guitar is a effectively a Fender Strat, choosing a pickguard that places the pickups in the proper location is the first key to trying to achieve the tones that I want.

This link: http://www.till.com/articles/PickupResponse/index.html provides tones of useful information on pickup placement.

I have purchased a 2 humbucker pickguard for a Strat from AllParts that appears to have the pickups in the proper locations. Since the Strat is a 25 and 1/2 inch scale length, I need the neck pickup to be 6 and 3/8 inches from the bridge.

What I think I want

With this guitar, my intent is to be able to capture the tones that I want in the form factor that I want.  I've picked out three tones that I definitely want with the flexibility of adding two more (with a typical 5 way switch).

I'm primarily looking for a Stratocaster neck pickup tone, an ES-335 style neck pickup tone and a Les Paul bridge tone.

This is a pretty tough combination to go after, especially since I tend to like the form factor of a Stratocaster. But for now, I'll just focus on electronics...