OmniTec-67A

About the OmniTec-67A

Inspired by the Altec 1567A: the early-1960s tube mixer with a signature green plate and a whopping 97dB of gain — the box behind a huge slice of the Motown sound.

The OmniTec-67A is a vintage tube preamp built for one thing: turning a sterile digital signal into something with grit, density and character. This isn't a clean gain box. The original Altec 1567A was a rack-mounted tube mixer with a simple two-knob EQ and enough gain to redline anything you fed it, and engineers used exactly that to their advantage. We modelled its drive-tube input and output stages so you can push a source into saturation, harmonics and subtle distortion — the raw analog tone Motown records are made of.

Motown's secret sauce, modelled tube by tube

The 1567A heavily influenced the sound of countless Motown hits, from The Supremes to The Temptations, and was famously worked by engineers like Russ Terrana and Matt Wallace. It's impossible to picture those records — the purposefully distorted brass, the oversaturated electric piano, the fat bass and vocals — without the sound this box made. After the Motown era it stuck around as a cheaper route to a coloured tube tone, and it never really left. Under the hood, the signal runs through a mic input transformer into a premix amplifier (the first half of a 12AX7), through an input control and a single-stage booster into the EQ, then into a further tube network (third 12AX7 and a 6CG7) and an output transformer for that extra oomph. We recreated the whole chain with our real-time circuit simulation, so the drive builds the way the hardware's does.

Three tubes, two bias voltages, one filthy tone

Where the original gave you one voice, the OmniTec-67A gives you three. The Tube Type control (A, B and C) swaps between three modelled valves, each with its own frequency response, output gain and harmonic range — go from a polite warm-up to full crunch just by changing tubes. A two-position Bias switch (Low or High) then sets how hard those tubes are driven: run them cold and the valve sounds thin; run them hot and it oversaturates — two discrete voltages, not a continuous sweep, so it's easy to recall. A Mic/Line switch chooses the input character (mic vs. line impedance, auto-compensated at the output), Phase flips polarity at the input, and the wet/dry Mix knob (0–100%) lets you dial saturation in parallel so you keep the dry punch underneath. Input gain (±15dB) and Output level (±15dB) let you set exactly how hard you hit the tubes and how loud you leave the stage.

Using the OmniTec-67A on vocals, bass and drums

On vocals, a hotter tube and a touch of bias push add the throaty midrange grit that makes a modern take sound recorded-to-tape. On bass and electric piano it delivers that saturated, harmonically dense Motown weight — try it on a DI'd bass to fake a room and an amp at once. On drums it turns thin samples into something that thumps, and on a full bus it adds cohesion and colour. The added vintage 3-band EQ shapes tone right where the tubes are working: Bass at 50Hz (±12dB), Mid at 400Hz (±12dB) and a sweeping Treble shelf whose corner slides from roughly 8kHz down to about 1kHz as you turn it (up to ±20dB) — more control than the hardware ever offered. If you want dynamic glue rather than harmonic drive, pair it with the vari-mu OmniTec-436C compressor.

OmniTec-67A Features

Modelled drive-tube preamp stages

The 1567A's input and output tube stages recreated as a living circuit — mic transformer, premix 12AX7, single-stage booster, a 6CG7 network and an output transformer — so pushing the input builds real saturation, harmonics and grit, not a static distortion curve.

Three switchable tube types

The Tube Type control (A, B, C) swaps between three modelled valves, each with a different frequency response, output gain and harmonic range — from a gentle warm-up to full crunch without touching another knob.

Low/High bias switch

A two-position Bias switch sets how hard the tubes run: Low runs them cold and thin, High runs them hot and saturated. Two discrete voltages rather than a continuous knob, so the tone is easy to recall.

Vintage 3-band EQ

An added tube-flavoured EQ the original never had: Bass at 50Hz (±12dB), Mid at 400Hz (±12dB) and a sweeping Treble shelf that slides from roughly 8kHz down to about 1kHz as you turn it (up to ±20dB), shaping tone right where the tubes are working.

Mic/Line input switch and gain staging

Select mic or line character — each with its own frequency response and impedance behaviour — with the output stage auto-compensated so levels stay usable as you switch. Input gain and Output level (±15dB each) set how hard you hit the tubes and how loud you leave.

Phase invert and wet/dry Mix

Flip polarity at the input to avoid cancellation in the mix, and use the Mix knob (0–100%) to blend the saturated signal against the dry for parallel drive that keeps transients intact.

Modelled VU metering

A faithful VU meter (reference level -14dB) shows how much drive you're generating so you can push the tubes with your eyes as well as your ears.

Authentic circuit emulation

Our real-time, SPICE-type component-based circuit simulation captures the sound and feel of the analog counterpart in every nuance, transformers and tube stages included.

SSE2-optimised code

DSP operations are pipelined on the SSE2 instruction set for high-performance operation, even under complex processing.

HighDPI / Retina support

Crisp, high-pixel-density rendering on macOS and Windows for a sharp interface on modern displays.