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Dual Sample/Track & Hold + VC Portamento
A compact powerhouse of control and modulation, this module combines two independent Sample & Hold circuits—each switchable to Track & Hold mode—with the classic Serge NTO-style Voltage-Controlled Portamento.
In Sample & Hold, each section captures and holds an input voltage whenever its Gate input goes high. Flip to Track & Hold, and the input passes through continuously until the Gate rises, freezing the voltage at that exact moment. Clean, precise, and perfect for both audio-rate and CV manipulation.
Paired with these is the beloved VC Portamento (VC Slew) circuit, designed to smooth the stepped voltages coming out of the S&H sections. Use it for expressive note glide, shaping modulation, or softening harsh transitions in generative patches.
For more experimental work, the S&H sections excel at "bit-crushing" an incoming signal—simply clock the Gate with an external oscillator to generate crunchy, rhythmic, and lo-fi textures.
Whether you're quantizing pitch, sculpting modulation, creating stepped random voltages, or exploring generative behaviors, this module provides a deep toolbox for sonic exploration.
Technical Description
The Dual Sample/Track & Hold + VC Portamento module implements two precision S/H channels alongside a classic voltage-controlled slew (portamento) processor. Each section is engineered for low noise, accurate voltage capture, and stable, predictable behavior in both audio and control-voltage applications.
Sample / Track & Hold Architecture
Each S/H channel uses a buffered input stage feeding a low-leakage analog switch that charges a dedicated hold capacitor. In Sample & Hold mode, the module captures the input voltage whenever the Gate input goes high, storing it with minimal droop for long periods.
In Track & Hold mode, the input signal passes through continuously (“tracks”) until the Gate transitions high, at which point the voltage is frozen at its exact level.
A precision output buffer ensures low impedance and excellent stability, allowing the captured voltage to drive multiple downstream modules without degradation.
Gate Conditioning & Mode Control
Each Gate input is conditioned to ensure reliable switching at both slow modulation rates and audio-rate frequencies. This enables everything from traditional stepped CV generation to high-speed “sample-rate reduction” effects when clocked rapidly.
Front-panel switches select between Sample & Hold and Track & Hold operation, routing the control signals appropriately for each behavior.
Voltage-Controlled Portamento (VC Slew)
The module includes a voltage-controlled slew limiter derived from classic Serge glide circuitry. The input signal feeds a current-controlled slew core where both rise and fall times are shaped by the control voltage. This architecture supports:
Expressive pitch glide
Smoothing of stepped voltages from the S/H sections
Dynamic modulation of slew time via external CV
Because the slew stage operates as an analog current integrator, it handles both audio and CV with clean, predictable response.
Inter-Section Workflow
The three sections are designed to complement each other:
The S/H channels generate stepped or captured voltages.
Track & Hold mode allows pass-through until a precise freeze point.
The VC Portamento smooths those steps, producing natural glides, transitions, and shaped modulation.
This makes the module highly effective for generative systems, pitch processing, and modulation sculpting.
Audio-Rate & Experimental Use
The switching elements can operate at audio frequencies, enabling creative techniques such as:
Lo-fi “bit-crushing” of audio
Rhythmic chopping or gating
Audio-rate sampling of modulation
Complex pattern generation when clocked from oscillators or dividers
When combined with the VC Slew, it becomes a flexible tool for shaping both tonal and modulation behavior.
LGE005 DIY Build Documentation:
LGE005 Bill of Materials
LGE005 PCB Layout w/ Designators
LGE005 Schematic
LGE005C Wiring Diagram / Schematic
LGE005C Bill of Materials
LGE005C Layout w/ Designators
Mechanical Parts BOM generally required for building Low-Gain Electronics Modules
** 4U Modular is a term used for the format most commonly known as “Serge Format” or “Loudest Warning Format”. Out of respect for the ever growing format, 4U Modular is the easiest way to refer to it. More Specifically it refers to the panel height and mounting hole style. 4U Modular will patch up just fine with other 4U "Serge" formats such as "Random Source", but it will not mount in RS boats or Buchla Boats (or power off Buchla power for that matter). An info page about this will be added to the website soon to make this a lot more easy to understand.
Details:
PCB Size: 6” x 2”
Current Draw: TBD