DoublePlusBass

 Yo, it's the first PCB I designed!

This circuit, the DoublePlusBass, represents the culmination of a LONG journey starting with my first complex point-to-point success (a TR-808 kick drum) and wanting a 909 style kick drum. Couldn't get it. Failure after failure.

Thomas Henry's Bass++ is a miracle of minimalist complexity, wringing a very capable and versatile kick drum voice out of a single LM13900 and a dual op amp. Quick note: there's a .pdf on that website that is AMAZING you HAVE to see it okay fine here's a link my god it's a thing of beauty.

So, I got massive kicks out of Thomas Henry's excellent work, but I wanted more flexibility and less "crosstalk" between settings. Which involved more parts. I wanted a pitch envelope that made the kick pitch more similar to the 808, which sags right at the end vs. the 909, which spiked downward fairly quickly after the attack.

Feature creep crept in, with every problem being solved with more buffers, so my own kick drum diverged significantly from the Bass++ inspiration, so the DoublePlusBass was born.

All my schematics had been hand-drawn up to this point, but the DoublePlusBass was super complicated, so I was struggling fitting all the schematics neatly on one page. Yes, I resorted to cutting and pasting. But then I started investigating electronic design applications, and after much frustration, landed on EasyEDA, which runs in a browser, which kinda rules.

After getting the schematic drawn, my mouse crept up to the "create PCB" menu item so with much trembling and quaking, I clicked it. POW!!!!! All my parts were there, on a blank field, ready to organize and trace. Incredible. Mind-blowing.

I've never had success with any kind of 2 dimensional prototyping. 3D is where my brain lives, where my circuitry took shape and gained life. BUT!!!! The 2 dimensions of a PCB somehow did click, so ...

... to make a long story not any longer, this is my first PCB. The current prints are a lot better in layout and whatnot, but the ELEVEN potentiometers are still laid out like they were, and the functionality is basically the same.

Okay, I'm actually NOT going to list everything that each pot and jack does, I'm in a hurry, but here's the biggest surprise: the 808/909 envelope moves the fundamental pitch up a great deal when turned toward the 808 side. The 909 starts high and drops to the fundamental pitch. The 808 hits its fundamental pitch right away, and sags down from there. So my least solvable problem was this: that knob fades between two theoretical fundamental pitches, but there's only one pitch CV, which ... the user has to turn lower when choosing a more 808-style pitch envelope.

Okay, that's all for now.