Mod #3: Varitone Variation
What it is: The original Varitone, which appeared in such vintage Gibsons as the ES-345 and ES-355, is a controversial circuit. In lieu of standard treble-cut caps and pots, it employs a rotary switch, with each position routed through a different-sized capacitor. It also calls for an inductor, which creates a series of notch filters. (In other words, the circuit doesn’t remove all signal above a certain frequency, but only a certain amount above and below that frequency.)
While the Varitone has its fans, it was never very popular. Detractors argue that it sucks tone, and its settings are too thin and “quacky” for many players. But even if you don’t dig the original Varitone sounds, you can use its general concept to great effect. (For example, if you omit the inductor, you lose a bit of the peaky resonance that alienates some players.)
The benefits: Multiple capacitor schemes can provide instant access to a wide range of favorite settings, plus others not available from a conventional tone control. Instead of fiddling with a pot, you can leap to the desired tone with the flick of a switch.
The cost: When you replace a tone pot with a tone switch, you lose access to settings that “fall between the cracks” of the switch positions. You also need various switches and caps, depending on how you configure the mod.
How it sounds: I wired up a multi-cap, two-switch tone circuit in a “parts” Jazzmaster with P-90s and flatwound strings. Ex. 3a demonstrates my three treble-switch settings. You hear my three bass-cut settings in Ex. 3b. As with the PTB mod, the variations can be subtle with clean tones. But when I add a custom germanium booster in Ex. 3c, everything gets much more dramatic. The entire clip is performed on the bridge pickup—the only things changing are the tone switch settings.
How it works: A conventional tone circuit uses a single capacitor, which cuts tones above a specific frequency. (The cap value determines the cutoff frequency.) Advancing the pot directs more signal through the capacitor to ground for a darker sound. You’re varying the amount of cut, but not the cut frequency.
Multi-capacitor switches let you choose your own set of cutoff frequencies, but once a capacitor is engaged, it’s engaged all the way. So instead of cutting varying amounts of signal at a fixed frequency, you cut fixed amounts of signal at varying frequencies.
Diagram 3a shows the basic idea. The center lug of the rotary switch connects to lug 3 of your volume pot, like a conventional tone control. You weave capacitors of escalating value through the lugs lining the pot’s perimeter, so that when you move the switch, a new cap is engaged. The other terminals of the caps go to ground—usually by bundling them together, wrapping them in heat-shrink tubing, and soldering the assembly to a ground point. (Most rotary switches let you specify the number of active positions via a notched washer on the pot’s shaft.)
This is a cool mod, but there’s one good reason not to bother: Someone beat us to it. This is precisely how Stellartone’s ToneStyler replacement tone pots work. They’re fine products, and if you can afford the cost (models start at $75 street), I recommend them. Photo 3a shows my homemade part alongside a ToneStyler—which would you rather put in your guitar? (Plus, I hate the stiff, clunky feel of the commonly available rotary switches.)