varitone

[colin trueman]

I'm going to build a 6 position varitone switch for my guitar.The switch I have picked up from maplins is a alpha 6 position rotary switch but it has 12 solder lugs + the earth lug.Each lug is numbered 1-12,Do i just use 1-6 or have I got the wrong switch?

[soulsonic]

The easiest way to find out is to use a continuity tester (like the kind most multimeters have - those ones that beep) and dial through the positions to find what contacts with what. Having 12 solder points suggests that it may be a 2 pole switch, which would be just fine and still perfectly usable for what you want. Attaching a knob and dialing through the positions will certainly tell you right away whether you have the correct number of positions. It's also very common to have extra lugs that aren't actually used - they usually have one design they use for everything and they then just set it for the correct index depending on the number of positions it's intended to have and leave the rest unused.

[colin trueman]

Thankyou very much for the reply you have been a great help

[Andre]

Colin,

If you remove the hex nut from the rotary switch, you will see a metal washer with a small pin sticking in the rotary switch.
If you lift the washer and move the pin to another hole you can change the number of positions.

André

[d95err]

Just out of curiosity: what choke or transformer are you going to use for the varitone?

[Mark Hammer]

6-position, 2-pole switches are quite common (i.e., even Radio Shack has sold them).  You have the "right" switch, just more switch than you needed.  Just a couple of comments to make. 

First, although the most common arrangement of rotary switches is for each set of contacts to move in the same direction (i.e., two clicks over is the same number of "spaces" from the common for each set of contacts), I've seen switches where one set of contacts "moved" in the opposite direction.  So, just to avoid heartache, once you have the contact arrangement mapped out, either verify that they both work the same way or mark off the contact set you have checked, just to make sure you ARE wiring it up the way you think you are.

Second, this will pop.  The fact that the rotary switch is normally wired up to select between caps and leave the unselected ones disconnected means that each time you move the Varitone switch you will hear a pop.  It is a trivial matter to just turn down the volume when you want to use the switch, but remembering to do so can sometimes be hard.  An alternative to the traditional arrangement is to use a series arrangement of capacitors, such that the junction between each cap in the series is soldered to the next contact, and the switch essentially selects not another cap but the next junction in the chain.  This arrangement results in much less pop because all caps are always connected to ground such that no charge can be stored up anyweher, waiting for the moment when you move the switch to that cap and the charge can be set free.  The downside of this is that calculating the required cap values can be tricky and the switch might get a wee bit crowded, since the caps will likely be bigger values than the stock Varitone.

Again, Gibson players have managed to get along very nicely with the standard switching all these years so it may be perfect for you.  On the other hand if you anticipate switching it around a bit in live contexts, then maybe you want to consider the series wiring arrangement.

Third, not all Varitone positions are pleasing for all players.  One of the perks of having "more switch than you need" is that you might use one set of contacts for, say, 4 of the positions, and the other set of contacts for positions 5 and 6, perhaps using them for some other sort of tonal change.