API Preamp

API Preamp concentrates on the Class-A 212L input circuit, with selected conveniences from the Vision console. It is not the full API Vision Channel Strip: there is no compressor, gate, sweep-filter module, or selectable equalizer to configure. The streamlined design is useful when preamp tone is the goal and DSP economy matters across many channels.

Separate mic and line controls provide different drive ranges. The modeled input section supplies the coloration, while the output control adjusts level without adding its own color. That separation lets you compare cleaner and more driven settings without letting a louder output dictate the preference.

In an Apollo Unison slot in Console or LUNA, supported preamp controls interact with the hardware and its input impedance. In an ordinary insert, the plug-in still processes the audio but those physical Unison interactions do not apply. Begin with the appropriate input mode, use gain and pad to manage drive, remove unwanted rumble if necessary, and finish with output level matching.

Manual — sections: API Preamp Controls; Unison Integration; Input Select; Output.

• Input Select: The INPUT button selects MIC or LINE and activates the corresponding gain control. The red LED identifies Mic; the green LED identifies Line. Select the operating path before setting gain because the two controls have different ranges.
• Mic Gain: 30–65 dB, with 40.5 dB identified as the plug-in's default unity setting. More gain drives the modeled preamp harder. Clicking the API logo restores that default; the printed gain value should not be mistaken for an equal amount of net gain added to an ordinary DAW signal.
• Line Gain: 0–12 dB, default 0 dB. This separate line control comes from Vision-console functionality rather than the original standalone 212L module. Use it for more restrained line-level gain staging.
• Pad: Red LED on means engaged. Mic mode attenuates by 20 dB; Line mode attenuates by 6 dB in ordinary plug-in operation. Use it when unwanted overload remains at low gain. The manual explicitly makes PAD unavailable with Line selected in Unison, so do not assume the ordinary-insert line pad is always available during hardware tracking.
• Phase / ø: Inverts polarity when its green LED is lit. Compare normal and inverted settings when combining microphones on the same source; it is a polarity flip, not a variable phase-alignment tool.
• Cut Filter: Enables a fixed 50 Hz low-cut filter with a 6 dB/octave slope. Use it for rumble and unwanted low-end energy, not as a substitute for the Vision strip's continuously sweepable filters.
• Meter: The LED ladder reads the preamp's output. Watch it while adjusting gain or pad, then also check the destination level in the host.
• Output: −24 to +12 dB of clean gain, default 0 dB. Reduce it after increasing preamp drive to judge tone at comparable loudness. Clicking 0 returns unity.
• Power: Its lit LED indicates active processing. Turning it off bypasses the plug-in; DSP savings depend on LoadLock. In Unison Gain Stage Mode, supported gain and output parameters can also be adjusted from Apollo hardware.

Manual — sections: Input Select; Mic Gain; Line Gain; Pad; Phase; Cut Filter; Meter; Output; Power.