I decided early on to add a tone control to this puppy, and the circuit is Jack Orman's modified BMP. I built the "New AMZ" version, but I do want to try the second variation at some point.
I knew it would be a tight fit, and it was. I need to recalibrate my thinking when I do stompboxes. I'm used to using high-voltage capacitors and full-size (say 24mm or so) potentiometers, and I keep those "in stock." Now I need to get more small (16mm) pots and low-voltage caps. I have some, but most of the ones I bought are 63 or 100 volts, and those are a bit too big. These circuits generally don't need caps rated that high.
Anyway, I put the board in the box and wired it up to test and it worked fine. You can see the test stage in the picture at the top. Looks like a mess, but the leads will get trimmed and tidied up.
Here's the finished wiring. It is tight...and did I say these parts are small? A couple of notes here. I decided to wire it for 18 volts - two 9 volt batteries in series - to get more headroom. Also, I took off one of the 2.2 uF caps (it's C3 - where the arrow is) to lower the gain.
This is a clean boost, and I found with the volume up all the way, it would distort. I'm trying to avoid distortion in this build - I just want a bump in gain. I have other boxes for distortion.
I have these way cool blue knobs I got from Small Bear Electronics in Brooklyn. Turns out they won't fit all the way down onto the shafts on the pots, so I had to open the bottom up a bit (drill joke...hee hee) with a 5/16 drill bit. I just did it by hand.
Argh. Vhut ees dat? No no no no no!
I had a setback. After I had the whole thing together, I discovered I had scraped up the paint on the box in a few spots when I was tightening the nuts for the pots. It bugged me so much I decided to repaint the box.
What I did was unbolt the pots and jacks and drop the whole assembly out. That's what we have here. I should be able to just drop it back in after the repainting is done.
And I need to be very careful on the reassembly!
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