Thursday, 31 May 2018

Rampage

The second kit from Befaco I built is the Rampage.

And it is not for the faint of heart.

Befaco Rampage

The kit is good quality (as was the A*B+C).  However, with 227 parts (about 560 pins to solder), 3 connectors and around 40 jacks, pots and various switches, I wouldn't quality it as easy.




Rampage kit


















I chose this module as an alternative to Make Noise's Math, one of the most recommended module in forums.  With some exceptions, Rampage fills the same roles.  Moreover, it is available as a kit which fulfills my desire to build my synth as much as I can.

Main board close-up


According to Befaco website :
"The module is built around two voltage controlled integrators. Integrators (also known as Lag Processors or Slew limiters) allow you to process your voltages, converting sharp square waves in ramp-like waveforms.
These lovely devices can, for instance, convert a gate signal into a simple envelope, or achieve a “portamento” or “glide” effect when applied to pitch CV."


A properly patched Rampage can assume more than 20 different functions : envelope generator, oscillator, comparator, polyrythmic gate generator, trigger delay, etc…

Before mechanical assembly
Assembly instructions are similar to the previous kit : same advantages, same drawbacks.

With a kit of that size and density, you have to be systematic in order to make sure to be "good first time".  Debugging such a circuit afterwards was not in my intentions.

Calibration of the triangle shape
 
I estimated that the two Schottky diodes of the kit were too large for the PCB footprint and I replaced them by some in my stock.

I also found an oddity in the presence of a solder joint below one of the potentiometer.  I reckon there should be enough room between the back of the pot and the joint when the pot is tightly attached to the panel, but I decided to mask it anyway with some insulation tape.

Better safe than sorry.













Still, I implemented the mod presented in this Muff Wiggler thread to ensure reliable gates by soldering 1M pull-downs resistors at the outputs.

Additional pull-down resistors

Finally, a photograph of the Befaco boys in action and a bit of sound.

Befaco boys in action




Here above, Rampage channel A is programmed as an LFO which frequency is determined by the output of the S&H and cadences the patch.  Channel B is the envelope triggered by channel A and whose attack is also determined by the ouput of the S&H.
A*B+C plays the role of the VCA.   The sound source is the pink noise from the S&H module.
The sound is coming out via Rings (whose parameters are, ... guess what ? ... controlled by the output of the S&H) and the phaser.
Additional effects : NI Supercharger, TAL Reverb II & LoudMax

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