Unlike most of my small-board projects there's no room on this one to add the MOTM power header or mounting holes. I'll still be happy to sell you boards without panels, but you're on your own as far as getting them into your preferred format is concerned. The pots are set 1" on center & are Alpha 9mm-type parts if you choose to go with board-mounting.
I've reposted littlem4tt's image here, it shows the trace cuts (green) and jumper (blue) that need to be done to rev 1.2 PCBs.
BOM
Resistors
[7] 100k
[2] 20k
[1] 10k
[1] 4.12k
[4] 1k
[1] 330R
[2] 100R
[1] 1KTC SMT
Capacitors
[1] 10uF Electro (audio path)
[1] 4.7uF Electro
[1] 1.5nF Poly Film
[1] 22pF Ceramic
[2] 47uF Electro
[3] .1uF Ceramic
[3] .1uF 0805 SMT
Pots
[2] Trimpot (20k)
[1] B or C50k Alpha 9mm
[2] B100k Alpha 9mm
Semiconductors
[1] 5.1V Zener Diode
[1] TL074B
[1] LME49710
[1] THAT2180B
[1] LM78L05
[2] 1N4001
Misc
[1] 10P 2-row Header
[2] PTC Resettable Fuse (.05h/.1t)
[2] Ferrite Bead
[4] Kobiconn 16PJ138 (Jack)
Calibration Procedure:
1) Red probe to the pad on the PCB marked TP. ("Test Point") Black probe to ground.
2) Set offset control to max CW (full volume) or insert a +5V CV source into one of the inputs.
3) Use the trimpot labelled 'zero' to set the voltage @ 'TP' to 0.000V or as close as you can get.
4) Set offset to max CCW. (off)
5) Use the other trimpot to set voltage @ 'TP' to 305.00mV, give or take ~3mV (~1%).
It should then open fully to unity gain with a +5V CV signal. The 5.1V zener diode should limit the offset + incoming CV sum to ~5.14V, so if you mash it up to the diode's break point you'll get a little bit of positive gain with the unit trimmed to unity at +5.00V. If you want to ensure you get no positive gain, max out the diode by applying a CV signal greater than ~5.3V and calibrate to unity at that point.
If you like distortion I encourage you to tweak the trimpots to taste as you can really overdrive the chip by setting the zero-point (step 3) to a positive value. (*this is from memory so forgive me if I got something backwards...) The 2180 sounds really meaty when you overdrive the shit out of it. This is not a bad distortion module if patched/set up that way. 8_)
Alternative CV sensitivity is possible - you can set it up to accept 8V or 10V signals by changing the zener diode to an appropriate value and trimming as above. A different LM78Lxx regulator can also be used to supply the appropriate voltage to the offset control.
