CometVintage Distortion

From the vendor

A classic distortion pedal that has been in continuous production for over 40 years, blending ideas from the Big Muff, RAT and Distortion+.

The Comet Vintage Distortion is a clone of the classic orange BOSS DS-1 Distortion, one of their earliest compact effects in continuous production since 1978.

The DS-1’s design is an amalgamation of a few different ideas. The initial transistor gain stage is very similar to the Big Muff, as is the tone section with its bass/treble balance control. The IC gain stage followed by diode-to-ground hard clipping is similar to early op-amp distortion circuits like the MXR Distortion+ or Pro Co RAT.

During the past four decades, it has undergone several revisions. The basic schematic structure has stayed the same throughout its production, but when the original IC was discontinued in the early ‘90s, the op-amp gain stage was redesigned to use a standard dual op-amp. Previously it had used a Toshiba TA7136P special-purpose “RIAA preamp” that was technically not even a true op-amp, so this necessitated several changes. They also re-voiced the circuit at the same time, reducing the bass and increasing the treble slightly.

The result is that there is a significant difference between the “pre-1994” and “post-1994” versions of the circuit. The pre-’94 version remains highly regarded, while the post-’94 circuit is responsible for the DS-1’s reputation as a poor-quality beginner’s pedal. The good news is that the voicing changes are fully reversible, and it’s possible to get the post-’94 dual op-amp version to sound just as good as the pre-’94 version with a handful of capacitor changes.

The Comet is based on the dual op-amp version of the circuit. The default build calls for a few parts substitutions to make it nearly identical to the pre-’94 circuit. If you want to use the TA7136P chip for an exact replica of the pre-’94 DS-1, the legacy version of the Comet is still available and supports either configuration. This updated version drops support for the old IC because it’s almost impossible to find today and the build process is much more streamlined without the option.