AstraSilicon Fuzz

From the vendor

An early silicon fuzz from 1966 that was also sold as the Sam Ash Fuzzz Boxx. One of the first drive circuits to include a tone control.

Project description

The Astra Silicon Fuzz is a clone of the Astrotone Fuzz, also released as the Sam Ash Fuzzz Boxx (yes, there are three Z’s and two X’s!). It was manufactured by the Universal Amplifier Company in New York City from 1966-1968.

The Astrotone was one of the first silicon fuzz units, developed in an era when germanium transistors were still widely used. It’s also one of the first effects pedals to feature a tone knob, although it’s not particularly effective in this circuit (at least not without some modifications) and later fuzz pedals such as the 3-knob Tone Bender greatly improved upon the concept.

Analogman released his version of the Astrotone, conveniently also called the Astrotone since the original trademark had expired. It has the exact same topology, but has several component values changed out to round out the tone and remove the thinness of the original. It’s not an exact clone, but it’s still very highly regarded. A parts list for the Analogman version is provided in the build documentation alongside the original version.

The updated version of the Astra includes a toggle switch to select between three different sets of clipping diodes. Since the circuit uses hard clipping with no volume recovery stage afterward, the clipping diodes will directly impact the maximum available volume.