Valve Wizard Engineer’s Thumb

A little blog update: You may have noticed there wasn’t a post yesterday and that there is one today. Why on a Tuesday and not a Monday? Some big-ish changes are coming to the site in the near future, which (along with a bunch of other small things) is taking up a lot of my free time. So don’t freak out. I’m still here. Layouts are still coming. Just not quite as frequently (2 a week instead of 3). Now that that’s out of the way…

Here’s the 5-knob version of the Engineer’s Thumb compressor. Been meaning to do this one for a while and decided to do it in Eagle. It’s generally considered a Dyna-Comp/Ross Comp killer, and uses one side of an LM13700 chip in place of the old CA3080. This one will fit in a 125B with all 5 pots board mounted. The Bright switch is off board, but that’s just 2 wires. If you don’t feel like etching, you can get a board fabricated off OshPark. Original info on the circuit by the designer can be found here.


Build doc here with schematic, BOM, and drilling template.

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