Pittsburgh Modular Synthesizers: Laboratory Oscillator 1 – A Voltage Lab 2 Deep Dive

The Voltage Lab 2’s Laboratory Oscillator 1 is introduced as a central voice in the system, immediately setting itself apart with its wave folding architecture. Pittsburgh Modular’s penchant for organic, lively analog tones is evident here, as the oscillator is designed to be more than a basic tone generator—it’s a playground for complex sound design. The video wastes no time in highlighting the oscillator’s center clipping feature, which splits the waveform into positive and negative portions for independent manipulation.

This approach to oscillator design is all about giving users hands-on control over the harmonic content and dynamic behaviour of their sounds. The center clipping and wave folding circuits invite experimentation, making the oscillator feel less like a static source and more like a living, breathing part of a patch. For those who thrive on sculpting tones at the voltage level, this is a promising start.

Laboratory Oscillator 1 offers a suite of classic and unconventional waveforms, including sine, triangle, sawtooth, and pulse. Each is accessible via a straightforward interface, and the video demonstrates how these shapes respond to the oscillator’s folding and clipping circuits. Notably, there’s a random mode, clocked internally, that injects a dose of unpredictability into the proceedings—a nod to those who like their modulation a bit wild.

The oscillator’s warp mode deserves special mention. It generates harmonics similar to a square wave but in a form that’s more amenable to wave folding, sidestepping the usual sonic limitations of folding a pure square or sawtooth. This opens up new textural territory, allowing users to coax both familiar and alien tones from the same core oscillator. The demonstration makes it clear that each wave shape interacts differently with the folding and clipping, offering a broad palette for sonic exploration.

The center clipping circuit is a highlight, letting users independently modulate the positive and negative halves of the waveform. This is not just a visual trick—the sonic results range from subtle harmonic shifts to more radical transformations, depending on how far you push the controls. The AGC (Automatic Gain Control) circuit comes into play here, compensating for level changes introduced by clipping and maintaining a consistent output volume, albeit with its own characterful quirks.

Further manipulation is possible with the focus and offset controls, each adding their own flavour to the resulting sound. The video shows how these parameters can be voltage-controlled, with dedicated CV inputs for offset, positive, negative, and timbre. This means that Laboratory Oscillator 1 isn’t just about manual tweaking—it’s primed for dynamic, evolving modulation within a patch. The unpredictability of the results, especially when combining different wave shapes and modulation sources, is part of the charm.

One of the Laboratory Oscillator 1’s standout features is its ability to process external signals through its wave folder. By patching in audio from elsewhere in the system—such as another oscillator or even a modulated pulse width signal—the wave folder becomes a powerful tool for reshaping and hybridising sounds. The video demonstrates this by routing Oscillator 2’s output into Oscillator 1’s timbre input, then modulating the result for evolving, complex timbres.

Multiple outputs are available, each representing different stages of the signal path: a pure sine, a seed waveform (which morphs between shapes but remains unaffected by folding), and the AGC output (which includes all the positive/negative manipulation and AGC processing). This multi-output approach means users can tap into the oscillator at various points, layering or routing signals for parallel processing. It’s a modular-friendly design that encourages creative patching and integration with the rest of the Voltage Lab 2 system.