Rasp Release Notes: Rev 1 PCB

The Rev 1 PCB is a blue ROHS-compliant PCB.

There are a few recommended improvements for the board (as at Jan 8, 2021). *Some will be migrated to the BOM.

Recommend using dual op-amp with no phase-reversal lockup issue, so NE5532 instead of TL072, especially for U2 and U4. (If NE5532 is used, the value of R222 can be increased for more dramatic effect, if you like.)
~~On the back of the board, J1 (Mod socket) install a 100nF capacitor between the end pins.~~ Optional: Do not install R52. Install a 10k and 22k resistor in series, dead-bug style (i.e. upright, joined at the top) in the R52 holes: the 22k onto the side that connects to J1 pin 3. At the junction point of these two resistors, solder on one leg of a 100nF capacitor (e.g. ceramic, mylar, not electrolyctic, rated at least 24V), with the other end connected to 0V (e.g. the outside-edge lug of the J1 or other convenient location.) This gives a kind of dual RC fiter: if the modulation is plugged in it is filtered at 7k, but also filters the dry incoming signal at 15k. (to be verified)
(If you are experiencing signal bleed issues from loud modulation inputs, then try e.g. 100k resistor from J1 underside to U4B pin 6 or the corresponding connections of R51 or R15. Caveat: this has not been tested.)

Update from Rev 0

Information

R43 and R44 are marked as 1 ohm on the BOM. You can do that, however it is best to have a ferrite bead there. Or, if this is too fiddly, feel free just to replace the resistors with wire links. The function (to reduce power supply noise) is pretty marginal and uncritical.
The LEDs are not used for visual indication, but just as diodes with large forward voltage drops: any LED over 2.4V is best. A blue or purple diode is the best option. Some green diodes (particular a green diode in series with a 1N4148 vanilla diode) may also be useful. Avoid red, orange, yellow. The LEDS limit the highest and lowest levels reached on higher “Sweep” settings.
The label for capacitor C7 is in self-isolation somewhere near Aitutaki in the Cook Islands. C7 is next to C6 on the PCB.
R222 can be 27k to 22k if input signals are quite high
R47 can be 68k to 47k if input signals are quite low
Turning the knobs fast with no input signal can produce low frequency thumps.