Quantizer

8 Channel Quantizer

clee Quantizer 4U synth DIY

Quantizers take continuously varying voltages and translate them into steps, normally 1/12 volt which can then be used by VCOs to play "in tune"

My goal was to create an updated version of the Serge Quantizer, which I always lusted after but never had.

This Quantizer includes 8 independent channels of quantizing which share common SCALE. BANK and HOLD/SAMPLE AND HOLD controls

Please see THIS NOTE on a recent recommended modification to the input circuit

This quantizer is capable of 24 notes/octave, allowing for quartertone scales.

There are 8 channels of quantizing.

Each channel is independent, but shares the scale and hold/S&H settings.

Scales are arranged in 2 banks of 16 each.

Both bank selection and scale selection are voltage controllable.

Hold/S&H has 2 modes which are switch selected. In hold mode VC will cause the quantizer to hold its outputs regardless of what is at its inputs. In S&H mode a voltage greater than the treshold will cause the Quantizer to sample its inputs, which will then be held until the next time the threshold is passed.

A Trigger pulse is output at PULSE OUT when the S&H is triggered

Scales:

BANK 1
0 Halftone
1 Whole Tone
2 Major
3 Major Pentatonic
4 Harmonic Minor
5 Aolian Minor
6 Minor Pentatonic
7 Blues
8 Dorian
9 Lydian
10 Lydian Dominant
11 Phrygian
12 Phrygian Dominant
13 Balinese Pentatonic
14 Java
15 Chinese

Scales:

BANK 2
16 Hindu
17 Hungarian Minor
18 Sus 4th
19 Dim
20 Aug
21 7th
22 Minor 7th
23 3rd
24 Minor 3rd
25 Tritone
26 Eight Tone
27 Quarter Tone
28 Greek Lydian QT
29 Aolian Quartertone
30 Equal Quartertone
31 Quartertone REPEAT

OUTPUTS

8 channels of quantized voltages.

A maximum of 240 steps with 0 to 10 volts in, relating to 10 octaves of quarter tones

An LED shows when CHANNEL 1 is outputting the root note voltage of the selected scale.

PULSE OUT outputs a trigger pulse when the S&H is triggered

CONTROLS

BANK SELECT: Switch and VC

SCALE SELECT: Knob and VC

HOLD voltage control with TRESHOLD pot

HOLD or S&H switch selectable

CHANNEL 8 INPUT GAIN (inverted unity to unity gain)

CHANNEL 8 VOLTAGE OFFSET

Quantizer Build Notes

The Quantizer is an advanced build. Parts count is high, it requires accurate calibration and a great deal of point to point wiring.

Documentation includes a BOM, resistor changes for 15V operation and for Buchla 1.2v/oct.

Maximum response times

Channel Response Time: 300us (or aprox 3k/second)

Channel to Channel Response: 40us

Scale Select Response Time: 31ms (aprox 32 times/sec)

Input Range: +/- 12v (negative voltages ignored)
Output Range: 0 to 10v

Channel 8 Bias Range: +/- 4.5 volts

Calibration Mode: Shorting the calibration header puts the Quantizer in calibration mode. The outputs no longer follow the inputs.

Outputs: Channel 1-6 = 0v to 5v, Channel 7= 7v and Channel 8= 10v.

The mode is used to adjust internal trimmers.

THIS PAGE IS FOR REV 2 OF THE QUANTIZER, INFO FOR REV 1 IS HERE

Buffer Board input modification

I've recently discovered an issue with the input circuit which could cause problems with other modules if a signal going into a Quantizer input is multed to it. The best solution is to add a small input buffer board to the quantizer. The mod is fairly simple, and buffer boards are available from me if you'd like to do the mod.

BuffInstalled BuffPhoto