Do It Yourself:


S&H front
see empty panel

This is sample and hold module equipped with other minor circuitry to make it more versatile - clock and noise generator. So far S&H core has been tested only and proven to be good enough. Dropout rate is in range of few mV per minute, and pedestal error less than 5mV. This is however core performance and may be degraded by following circuit - the lag.
What you see in the picture is just panel with pots and knobs made to check ergonomics.

V-RAN pot:
adjust "Voltage Randomness", i.e. sampled random voltage amplitude
T-RAN pot:
adjust "Time Randomness", that is time variance of sample periods
tuning of S&H clock generator
SLOW/FAST switch:
choose clock tune range
LIN/EXP switch:
setting linear or exponential ramp of the lag circuit
TRIG/GATE switch:
in trigger position makes Sample and Hold, in gate position - Track and Hold
LAG knob:
controls sampled voltage rise/fall slope
LAG CV knob:
attenuator of external LAG CV input (modulation ammount)
RATE CV knob:
attenuator of clock generator CV input (modulation ammount)
SAMPLE pushbutton:
manual sample or track, depending on TRIG/GATR switch position
2x signal IN, CV for clock (2) and lag (1), external clock
2x OUT, clock, white and pink noise, and slow randomm

Preliminary specifications
desired clock frequency range:
0.05Hz-20kHz using knobs and external CV.
input/output level:
at least 18Vpp around center GND
dropout rate:
offset error:
aperture time:


The panel is made of 3.5mm thick aluminium. Painted with aluminium primer and several layers of various acrylic spray paint to achieve slight "variable color" effect. Panel writings are made in PCB fab the same way as used for PCB silkscreen. Not the most acurate, because they don't really care about silkscreen quality, but better results can be achieved in any graphic company - see VCF page. It was then protected with acrylic transparent spray paint. When panel is printed, the drilling can begin. Hollows around pot holes (about 2mm deep), hide pot's nut, so knob can be mounted fraction of mm from the panel. It can be clearly seen on empty panel photo and with knobs removed.

krisak's design