A * B + C

To complete my synth, I recently bought 2 DIY kits from Befaco.

The first one is called A*B+C.

Finished module

The kit is  good quality and rather simple.

Before soldering

The A*B+C is a dual, four-quadrant multiplier with VC Offset.

It can perform different operations on its inputs :
- amplifier and inverter of A input.
- VCA on A, with envelope CV on B.
- VC offset generation with C input.
- attenuation/inversion of C input
- ring modulation of audio signals in A and B.

Moreover, the output of the the first channel is normaled to the mixer of the second channel.  So the module can serve as CV/audio mixer.

Before assembly

Assembly instructions are good but could have been clearer, especially for the final assembly.
A couple of photos wouldn't have been too much.  But I didn't encounter any major issue.

My only gripe was about some parts that had a larger size than their footprint on the PCB.  I had to replace the two Schottky diodes with those I had in stock and solder 2 couples of resistors vertically. One resistor even had to be soldered on the other side of the board.

Once again, nothing major in my view.

Profile view.  You can see the vertically mounted resistors

Finally, the module suffers from a high level of background noise as indicated in this Muff Wiggler forum thread.   Anyway, it does not seem prohibitive.   There is a suggested mod but it looks like it modifies the potentiometers behaviour, so I didn't want to perform it (and I didn't have the necessary 1/8 W resistors).   Time will tell.