Systech Overdrive clone with treble & bass controls in a 1590B2

The Systech Overdrive was introduced in 1975. I purchased back then and still have it (see last pic). They have become quite rare to come by. Original units are selling for as much as $599 and, IMO, they do sound really good, My version is an exact clone of one but with added BAX (treble and bass) controls, making it much more versatile. The original only had 3 knobs- Bandwith, Frequency and Gain. On my modified version, with the treble and bass controls at 12 o'clock, it sounds identical to my original. They came in a very large aluminum enclosure (see last pic of the original below for comparion), but my verison comes in a much smaller Hammond 1590B2 with all top jacks, and with a relayed true bypass. I used all Lumberg jacks and Wima film capacitors