Cool Toy!

[Pep]

I was looking through my archived items of interest and stumbled upon this little beauty. It sounds really cool. Anyone have an idea what it might be doing?

oops.. wrong link will update in a second

[Pep]

Looks like a bad link now. Here is the description from the Harmony central press release:

New from ElectroKraft is the "Tone Box," a tone enhancement stomp box designed to improve the sound of guitar or bass pickups and provide greater control over your tone.

The "Tone Box" is electronically known in the high end stereo world as a "passive pre-amp". A term coined by Hi-Fi stereo enthusiasts to describe a component used before an amplifier like an active pre-amp, but retains the true tone and sound of the amplified device. In this case the "Tone Box" retains the true, natural tone clarity of a guitar or bass.

Active pre-amps, on the other hand contain non-linear components (IC chips) that introduce some distortion causing the natural tone of the guitar wood and pickups to be lost according to the company. Since the "Tone Box" is a passive device there is no power supply or battery required.

The "Tone Box" is intended for the tone purist. ElectroKraft reports that customers have described the "Tone Box" as allowing them to dial in hollow body Jazz guitar sounds on a Strat or Tele as well as guitars with humbucker pickups. They've also described slight compression and pickup enhancement that allowed them to "tune in" an array of new tone colors.

Features:

True bypass footswitch.
Frequency control knob.
Tone saturation knob.
Coil switch. Provides 2 options of tone depth.
Standard 1/4" in/out jacks.
A cool retro look in an all aluminum stomp box package.
The "Tone Box" is hand made and can also be "tuned" to your style of playing to allow more bass frequencies, more treble frequencies, or more mid range frequencies to come through your amp. The "Tone Box" can also be custom made and tuned for bass players.

Available direct through ElectroKraft.com. $85.00 (Includes free shipping in the continental US). The "Tone Box" is covered by a lifetime warranty for the original owner. Full refund if not completely satisfied.

[David Schwab]

Sounds like it's an LC filter... more-or-less a Varitone control. They mention a coil, so it has an inductor, and probably a cap or two to tune the notch.

"Tone Box" as allowing them to dial in hollow body Jazz guitar sounds on a Strat or Tele as well as guitars with humbucker pickups."

You can't have a "passive preamp" but you can have a passive tone control.

Get a small transformer with a 10K primary (Mouser part 42TM-019) Use the primary side as an inductor... Alternately you can use a 5 to 6 Henry center tapped inductor.