This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Tuesday, September 5, 2017

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.

11 comments:

  1. Thank you so much (this phrase is very weak !)

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  2. I'm interested to know how this turns out for people, I did not have a very good time with this circuit (two knob)

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  3. Verified. Since I wanted to make signal paths bolder rather than ground, re-made a pcb by hand drawing based on the above PCB layout. Works very well. Thank you for great layouts!

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  4. Could we get a layout that uses a ca3080?. If i were to build this, could I ommit pots that I don't plan on using?

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  5. Stunning!!! Threshold, Ratio, Attack, Release, & Level !!!
    What more could you ask for?
    Look anywhere & everywhere and you won't find anything nearly as precision as this. This is truly remarkable.
    To have a compressor with these features and obvious potential quality available to the DIY community is simply phenomenal! I personally have been searching for several years for a compressor that I could build that has this kind of precision and quality. Now I've found it. Thank you so much!!

    To Jose & Kevin:
    There are lot's of simpler DIY Compressor circuits available here & elsewhere. Just click on the Compressor link under the "Type" heading above & to the left. You will find several very fine compressors that are not nearly as complicated.

    As for me I can't wait for my boards to get here from OSH Park!

    Thank you again! You guys Rawk! And for free ?!?!

    Will Kenworthy

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  6. Yesterday I built it, in guiatrra it works very well, today I try it with bass. I could prove that the release to the maximum distorts noticeably.
    Excellent project, thank you!

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  7. This comment has been removed by the author.

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  8. Yo, is it just me or is that ratio pot reversed?

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  9. Can I use lm13600 instead of using the lm13700?

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  10. Any chance of a perf board version?
    please?

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