New Year. New Challenge.

Ornament and Crime is one of the Eurorack modules constantly recommended in modular synthesizers forums, along with Math from Make Noise, Batumi from Xaoc or Clouds from Mutable Instruments.

If we add that it is basically an Open Source project, that it exists mainly as a kit and that there are several variations of the firmware, it goes without saying that I needed one. 

Front side

I decided on the Plum Audio version, a kit available from the Thonk online shop.   This improved version has input control in the form of attenuverters with LEDs, output voltage adjustment and a front panel USB connector.  

Let's avoid the financially painful episode of a post-Brexit purchase from a UK site and let's get to the point.
 

The kit

Ornament and Crime is a polymorphic control voltage generator.  It has four modulation inputs, four trigger inputs, four outputs and a micro-controller to handle them all.  

Bob cheks solder quality

The micro-controller is a standard Teensy 3.2, with an ARM Cortex M4 on board.  It comes pre-loaded with the official firmware.  
Depending on the firmware application, the module can act as an analogue shift register, sequencer, arpeggiator, envelope generator, quantizer and so on.  Hemisphere, one of the alternative firmwares, even offers to choose 2 modes simultaneously from a choice of about 60.

It was the four independent envelope generation function that made me decide that the module was useful for my usage, but I will experiment with the other modes of course.

 

micro USB parts.
Bob for scale

In the article about the Befaco Rampage, I wrote that the kit was not for the faint of heart.  However, this version of Ornament and Crime is two divisions above.  Not only is the density high, but there are some tough parts, such as the OLED screen, the micro-USB connector and the "pogo" pins (aka spring-loaded pins) under the micro-controller board.
 

 

 

 

 

Bob cleans up

The kit is very well thought out.  The two PCBs are well designed and very clear with the part number and value of each component clearly indicated.  The bags are organised according to the progress of the kit. The contents of each bag are listed on the label. The documentation is accessible via a QR code on the box.  It is minimalist and refers extensively to explanatory videos, which are very practical, but sometimes a little fast.

Despite the density and number of components, the assembly went smoothly given the quality of the kit.  As usual, I did many small sessions, methodically, calmly.  It was demanding but in the end I didn't have to correct anything.

 

Back side

The only anecdote worth mentioning is that the documentation asks to pay particular attention to the orientation of the bicolour red/green LEDs and indicates that some kits have been delivered with reversed LEDs (red instead of green and vice versa).  I did a quick check with other LEDs I have and concluded that this be the case.  I decided to solder only one of the 8 diodes legs before a final check.  Once the front panel was assembled, the test clearly showed that my diodes were the right kind and therefore assembled backwards.  Unsoldering everything, turning the LEDs over, re-soldering...
If I had been really smart, I would have tested with *one* diode *before* placing the front panel. 
 

User Interface board.
LEDs are reversed.

Once assembled, the module still needs to be calibrated.  The firmware guides all along the way but it is quite tedious to measure the 50 or so calibration points.  It took me almost an hour, including the time when I had to remember how to use the measurement ranges on my multimeter.  Fortunately, this is a one time thing.

Now I just have to get used to the beast.  We are far from the "one function per button" philosophy of analogue modules. Since this is a geeky project, parameter pages abound in each firmware application. 

Module is alive. 
Testing various options of the envelope generation.
The screen refresh is visible in the picture.