MOTM 101 Noise/Sample and Hold

The MOTM-101 is multipurpose module for the Synthesis Technology MOTM system. It functions as a flexible noise generator, and it also has a powerful sample and hold section.

The benefit of combining these two functions in one module is that the noise generator is hard-wired into the sample and hold section. This lets you create classic sample and hold effects without needing to patch the two together. While this saves patch chords, it doesn’t limit you. Each section can also work independently.

The MOTM-101 is an essential part of any synthesizer system. It is a dual-function module, where the Noise Generator is linked to the Sample/Hold section without the use of patch cords. Each section can operate independent of the other.

The Noise Generator

The noise generator section starts by creating white noise. This is available from a dedicated jack, and is great for making percussion, wave and many other sounds.

The white noise is internally patched into a low-pass filter. This creates pink noise, which is also available at a dedicated jack. Pink noise has a “darker” sound, and is better for using when you need a muted or dulled noise.

The pink noise is also filtered. It is heavily filtered, to the point that it creates an random output. The Random output is useful for modulating anything that needs a little weirdness added. Interestingly, the MOTM-101 also provides a dedicated Vibrato output.

The Vibrato output is the noise filtered so that it will provide sine waves that vary slightly in amplitude and frequency. The frequency centers around 7 cycles per second. This makes it sound somewhat like a natural vibrato. The irregularities make is sound much more realistic and lively than just using a LFO.

One final aspect of the noise section is worth noting. The Noise/Clock switch toggles the source for the vibrato between noise and the internal clock. This doubles your options for the Vibrato output.

Sample and Hold

The sample and hold is also very flexible. An internal clock can be varied with the Clock knob, adjusting how frequently samples are taken. The Trig light flashes with each cycle of the clock.

The sample and hold circuit takes a sample of the voltage each time the oscillator cycles. By default, the circuit samples the built-in noise circuit. The sampled signal is then held until the next cycle.

The In jack lets you patch in an external signal to be sampled. There is also an input for an external clock. This is useful if you wan the sample and hold to trigger at the same rate as another module, such as a keyboard trigger or a sequencer.

Finally, there is a Track/Hold switch. This modifies the way the Sample and Hold works. In Hold position, the module samples with each clock cycle, and holds the signal until the next cycle. In Track position, the output follows the input when the clock is low, but holds it when the clock rises above 1.5 volts.

The remaining knobs let you adjust the level of the output level and adjust the amount of slew, the glide time between subsequent values of the output.

In Use

The MOTM-101 is an extremely useful module. By patching the Vibrato out to a FM in on a VCO, you can add a subtle or for modulating a filter cut-off level, or even pulse width. The noise outputs are great for typical noise effects, but also can be great for adding a little weirdness or irregularity to the output of VCO’s. A little bit of the Random output patched into a VCO makes it warble a little, much like a natural instrument. Patching a sequencer trigger into the MOTM-101, and using the S&H output to modulate the sequences filter, results in a classic synth effect that is still an interesting effect.

The completed module is rock solid, with all the regular features of the MOTM line: high-quality jacks and pots, tough as nails paint finish, and nice big knobs and switches. The module is available as either a kit or a pre-built module. The kit is fairly easy to build.

Modules can be purchased directly from Synthesis Technology.

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