MOTM

I have used my Blacet Miniwaves mostly for quantizing, since I like to 
use scale tones in my aleatoric musings.  I've looked around for a 
dedicated quantizer, but never found anything well suited to a standard 
MOTM setup until this.  Not sure when it was added to the Modcan B 
lineup, but the Dual Quantizer 55B fills the bill.  I've updated my 
website with some photos and a two minute MP3 demo.

http://www.pugix.com/top-cabinet.htm#quantizer

The Miniwave does well as a quantizer.  Modcan offers a version of the 
Miniwave, too, with a built-in VCO.  There's a quantizer bank in the 
standard Blacet ROM.  The Davidson SCALE Quantizer ROM is excellent, 
too.  I'll speak to the differences between the quantizing with the 
Miniwave and the Modcan 55B in a bit.  First, about the physical Modcan 
55B module.

As you can see from the photos on my site, the 55B fits perfectly into 
my MOTM rack.  Although it's a thinner panel, the 1/16-inch difference 
of height (shallower than the 1/8-inch MOTM panels) is barely 
noticeable.  What *is* noticeable of course is the color.  The panel 
design is nice and clean.  The jack spacing and locations are different 
from MOTM.  The switches are mini-toggles, not bat-handles.  Alpha pots 
are used.  I replaced the knobs, not just because of the look, but 
because Modcan knobs have a gap in the flute that the set screw goes 
through, and your finger catches on it.  It's annoying.  Otherwise, 
build quality is very good; it's clearly assembled with care.  You'll 
notice that the hardware consists mainly of a large PIC 
microcontroller.  The six trimpots are labelled, but there's no mention 
of them in the instruction manual, which is very short.  It would be 
nice to have a calibration procedure.

Lead time on this was two months from placing the order and payment and 
receipt of the module.  I never ordered from Modcan before, but this 
seems about normal.  When I placed the order, Bruce Duncan responded 
quickly and asked what power cable I required.  He supplied a MOTM power 
cable adapter at no extra cost.

The 55B features.

There are two identical and separate quantizers.  Each has an input for 
the CV to be quantized, an output, a clock input and a pulse output, and 
three control inputs.  There are four parameters, three of which are 
under voltage control.  You manually select one of three fixed scale 
banks.  This isn't under VC like the Miniwave bank is.  Each bank has 16 
scales, selected by the sum of a pot and a SCALE CV input.  There is 
also a TRANSPOSE pot and CV input; the Miniwave has nothing like this.  
It is a key transposition, not just an offset.  (I don't really 
understand the difference.  Maybe one of you will explain it.)  Finally, 
there is an INVERT input that responds to a gate.  This simply inverts 
the output around ground.  If your input is all positive, when inverted 
it is all negative.  I didn't quite see the utility of this until I 
realized that negative inputs get quantized just fine, unlike the 
Miniwave, which needs a zero to +10V input in quantizing mode.  So you 
can merrily quantize a MOTM-320 LFO, using any of its waveforms.  You'll 
normally want to use an external attenuator on the input for overall 
scaling.  None of the inputs has a pot for attenuation, due to lack of 
panel space.

With nothing patched to the CLOCK input, quantizing happens when the 
input crosses a quantized boundary, just like with the Miniwave.  On 
each transition you get a short pulse out of the PULSE output.  It's 
something I have wished the Miniwave had. (I saw a schematic somewhere 
describing a pulse output Miniwave modification.)  My demo MP3 shows 
this off by using it to trigger an envelope generator to make a new note 
on each transition.  Now, I found that when quantizing the output of a 
sample and hold, the 55B works better if you clock it with the same 
clock used for the sample and hold.  It's cleaner, because with large 
jumps without clocking there can be a zipper effect as multiple 
transitions are crossed. The 55B makes a nice sample and hold by itself, 
with a no-droop digitized output.

I admit to general ignorance when it comes to scales.  But I can say 
that the choice of scales in the three banks has a good variety.  My 
favorite is the B bank, which includes Algerian, Altered, Aux 
Diminished, Balinese, Byzantine, Diatonic, Spanish, Double Harmonic, 
Hindu, Sixtone Symmetric, Nine Tone, Overtone Dominant, Pelog, 
Prometheus, Enigmatic, and Octatonic.  (These are listed on the Modcan 
website as being in the C bank, but the downloaded manual puts them in 
bank B and to my ear this seems right.)

Overall impression is of a very nice module that I will use a lot.  Now 
maybe it needs a few Modcan siblings in my cabinet.  The Clock 53B looks 
very interesting....

-Richard Brewster
http://www.pugix.com