52 F1shnet
A Workshop Computer interpretation of the Maestro FSH-1 filter/sample-hold effect. Envelope mode uses an envelope follower and ratio-style low-pass cutoff movement with a low base range, so rectified input dynamics move the filter like a low-pass auto-wah rather than adding a simple linear cutoff offset. Envelope sensitivity and output trim are scaled for modular/euro-level sources, so 5-6Vpp oscillators should move the filter without immediately pinning the envelope open or clipping the output. In the S&H gesture, random values move the filter frequency around the stored middle-page range with a wide pitch-style response rather than changing the envelope, with a moderate lower S&H cutoff floor, moderately damped resonance, and click-reduced ping-pong movement between the two audio outputs. Audio In 2, CV 1, and CV 2 all influence parameters, with CV 1 and CV 2 keeping the same jobs in every switch position. Pulse In 1 acts as an external clock / retrigger, and Pulse In 2 can also force the sample-and-hold gesture high. CV Out 1 always emits the stepped sample-and-hold voltage, CV Out 2 always emits the envelope follower, Pulse Out 1 mirrors the clock, and Pulse Out 2 emits the sample trigger pulse. Knobs use soft pickup when switching between middle and up so parameters do not jump until the physical control crosses the stored value for that page. Up exposes output trim and envelope sensitivity while Y remains the shared resonance control from the middle page; envelope release is fixed internally rather than user-facing.
Panel
Filter RangeDepthResonanceAudio InAudio Mod InCV 1CV 2ClockS&H GateLP Up / Ping OutLP Down / Pong OutS&H CVEnvelope CVClock MirrorSample TriggerControls
Filter Range
Base filter range / cutoff area.
Depth
Main filter modulation depth.
Resonance
Resonance emphasis for the core filter voice.
Alt Page: Switches the knobs to the alternate control page without changing the core filter voice; knobs use soft pickup.
Main Page: Default control page for the core filter voice; knobs use soft pickup when returning from the alternate page.
Sample Hold Gesture: Hold the spring-loaded down position to replace the envelope with random stepped filter movement; Main controls S&H clock speed while down is held.
Inputs & Outputs
Inputs
Outputs
Inputs
Audio In
Main mono audio input to the filter engine.
Audio Mod In
Secondary audio-rate control input used as extra parameter modulation.
CV 1
Consistent modulation for filter range and envelope sensitivity in all switch positions.
CV 2
Consistent modulation for depth; positive CV widens the envelope/S&H sweep, negative CV makes it shallower.
Clock
External retrigger / clock input. Forces a new random step in sample-and-hold mode.
S&H Gate
Qualified gate input that forces the sample-and-hold gesture high while held after a real low-to-high gate.
Outputs
LP Up / Ping Out
Fully wet envelope-up low-pass output; transients open the filter upward. During S&H gesture this is the left side of the ping-pong S&H low-pass voice.
LP Down / Pong Out
Fully wet envelope-down low-pass output; transients close the filter from the stored range. During S&H gesture this is the right side of the ping-pong S&H low-pass voice.
S&H CV
Stepped sample-and-hold control voltage, always available as a utility output.
Envelope CV
Envelope follower control voltage, always available as a utility output.
Clock Mirror
Mirrors Pulse In 1.
Sample Trigger
Divided sample trigger pulse fired once for every four newly sampled random steps.
LEDs
Alt Page
Lit when the alternate control page is active.
Main
Brightness follows Main; while Down is held it follows Down-Main S&H speed.
S&H Gesture
Lit while the sample-and-hold gesture is active from the switch or Pulse In 2.
X
Brightness follows the X knob position.
Main Page
Lit when the main control page is active.
Y
Brightness follows the Y knob position.
README
F1shnet
An FSH-1-inspired filter/sample-hold effect card for the Music Thing Modular Workshop Computer.
This version is an interpretation focusing on the core idea shared by the Maestro FSH-1 and recent descendants: a low-pass filter moved either by your playing dynamics or by random stepped voltages.
Modes
- Up: Alternate control page
- Middle: Main control page
- Down (held): Sample and hold gesture
Controls
- Middle: Main = filter range, X = envelope/S&H depth, Y = resonance.
- Up: Main = output trim, X = envelope follower sensitivity, Y = shared resonance.
- Down (held): Main = internal S&H clock speed with soft pickup.
Performance patching
- Patch Pulse In 1 as an external retrigger / clock.
- Patch Pulse In 2 to force the sample-and-hold gesture high without touching the switch.
- CV Out 1 is always the stepped S&H voltage and CV Out 2 is always the envelope follower voltage, so both can patch elsewhere even when the audio voice is doing something different.
- CV In 2 modulates depth strongly enough to be audible: positive CV widens the sweep and negative CV narrows it.