I originally had a 5-position version in a strat.  Because of the torque required to switch between positions you normally see these with a "chicken-head" knob (again, see "Lucille") which will screw onto the shaft and hold it firmly in place.  That just never looked great on a strat, so I spent a lot of time modifying the switch to accommodate a standard strat knob.  I cut the shaft down and pulled apart the switch to reduce the resistance between the positions, but I was never satisfied with it, so the switch itself was seldom used in spite of the cool sounds.

Currently I have another version one ready to be wired into another project that I haven't gotten to yet (although the schematics are already drawn and the components all purchased).  The cheapest rotary switch out there is a 12 position model available at Radio Shack for about $1.  Why not go with still more options?  This time I'm using it in a guitar that doesn't look so bad with the chickenhead since it is a bit of a frankenstein.

Note: Interestingly, a varitone will provide completely different results with different pick-ups because each pick-up's voice has a signature set of frequencies for the caps to operate on.

There is a varitone available as a kit through and another one at (they also have a "super varitone" with extra sounds from switching the range).

The values of the capacitors can vary, but the tables below provide a good range of tonal color.  Feel free to experiment.  However, the Griblin model was the best in my experience.  Results will no doubt depend on the pick-ups in your guitar.  Some values will produce a muddy signal, others will brighten your tone, other still will fall somewhere inbetween to give you a glassy sound.

My little monster At left is a varitone I built with on a rotary switch with a "chicken head" knob. This one has 11 capacitors (the 12th position being the bypass).  Details can be found below. To build your own, below are a few recipes.  Capacitor values are expressed in both microfarads (uF) and picofarads (pF) since many of these components are found with value expressed in either unit.

6-position varitone (Gibson's "Lucille" and Blueshawk models*)
 

*This is according to a couple schematics I found on the web.  Supposedly there are also resistors included in the circuit to balance the output level of the signal, but I don't believe they are required.

Incidentally, I tried the B.B. King model in the store on a couple occassions and did not find the effect to be as dramatic (or as useful) as with the Griblin version.  Of course, as with everything else in the search for the perfect tone, this all depends on the type of the pick-ups, your amp, effects, and the alignment of the planets!

The whole thing is going to be connected in parallel, so you should not have to take apart any of the original wiring except to physically substitute another (e.g., tone) control for the varitone.

Here are the steps: The capacitors are all soldered on consecutive lugs on the rotary, preferably in increasing order of capacitance.  If it isn't obvious which position is which, probe it with a continuity tester. Solder together the free ends of the capacitors (i.e., the ends not soldered to the switch). Run a wire from the merged free ends to the hot lug on the master volume (or, alternatively, directly to the jack; electrically it's the same thing). Run a wire from the common lug (most likely near the center of the bottom) on the rotary switch to any place in the ground side of the circuit. Play guitar!

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