Relab 176

This is the Relab 176 Compressor/ Limiter. Accurately modeled from the entire audio circuit of a vintage 1960s 176-style compressor: every tube, transformer, timing network, and power supply interaction is re-created using a real time circuit solver. This preserves the tone, timing, and dynamic behavior of the original hardware:

• Hardware-Accurate from Input to Output: The Relab 176 reproduces everything: the tone, timing, and dynamic behavior of the hardware. Every tube stage, transformer, and timing network responds as it does in the original.
• Compression That Adapts to the Music: Fixed-threshold, variable-gain design where ratio, drive, and source material interact to shape timing, curve, and harmonics.
• Instant Control Over Tone and Transients: Switchable interstage transformer, asymmetry detection, and calibration trims allow quick changes to character and transient handling.

Put the 176's tone, timing, and control into your next mix – and hear it for yourself.

Features That Preserve the 176's Sound - and Expand Its Workflow

Ratio-Driven Knee Behavior for Nuanced Dynamics

• The Relab 176 follows the original fixed-threshold design with four hardware ratios -2:1, 4:1, 8:1, and 12:1. Knee position and slope change with each ratio, producing compression that ranges from smooth leveling to assertive limiting.
• Compression intensity adapts naturally, ensuring nuanced dynamic shaping at every setting.

Program-Dependent Timing from True RC-Tube Interaction

• Attack and release times come from resistor-capacitor networks directly coupled to the tube gain stage.
• Timing is program-dependent, shaped by signal level, transient size, tube nonlinearity, and transformer interaction — not fixed millisecond values.
• The Fixed/Auto toggle changes how release adapts to the program.

Polarity-Selective Detection for Targeted Transient Control

The Sidechain Polarity control in the Relab 176 changes how the detector responds to the positive, negative, or both halves of the waveform. This lets you target specific transient edges — for example, clamping kick drum attack without touching low-end body, or controlling plosives in vocals without affecting overall presence.

Transformer Path for Sub-ms Attack, Resistor Path for Vintage Thump

The Stage Coupling switch changes how the variable-gain tube stage connects to the output amp:

• Transformer – Adds a transformer between stages for faster attack (sub-ms possible), subtle "smiley curve" tone, and reduced low-end wobble.
• Resistor – Uses a resistor path for slower attack, flatter tone, and more vintage-style low-frequency thump.

Both are authentic circuit paths and can be chosen for transient speed, tone, and low-end behavior.

Shift Bias, Harmonics, and Threshold in a Single Move

Calibration shifts the internal tube bias and balance – just like adjusting multiple trim pots on the original hardware – changing threshold, harmonic profile, and dynamic feel:

• Bias & Balance: Adjusts 6BC8 and 12AX7 tube operating points, influencing even/odd harmonic mix and low-frequency stability.
• Threshold Shift: Moves the point where compression begins without changing your input gain.
• Dynamic Response: Alters transient smoothness and micro-dynamics.
• Tone Shaping: Warms, brightens, or tightens tone depending on bias settings.

It's a single control that moves multiple internal parameters together, with extra flexibility available via the plugin's back-panel trims.

Advanced Bias & Level Tuning

• Click the Relab logo to access advanced controls: three hardware-style trim pots for 6BC8 bias, 6BC8 anode balance, and 12AX7 bias – plus a Reference Level control.
• Fine-tune threshold, harmonic mix, transient response, and low-frequency stability with the same adjustments available inside the original hardware, now with greater flexibility for gain staging and tone shapin.