Universal Audio
Century Tube Channel Strip
Combines a tube-style preamp, three-band EQ, and one-knob optical compressor for fast gain staging, tonal shaping, and dynamic control while tracking or mixing.
GUI Screenshot
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The Overview
A Straightforward Recording Channel
Century Tube Channel Strip follows a fixed left-to-right path: Tube Preamp, Equalizer, Opto Leveler, then Master. The preamp supplies gain-dependent coloration, the EQ handles broad tonal adjustments, and the optical compressor controls level with automatic compensation rather than a full bank of timing and ratio controls.
The EQ and leveler can be bypassed independently. This makes it practical to establish the preamp tone first, add only the EQ needed, and then bring in compression while checking the gain-reduction meter.
Tracking and Mixing
On a DAW track it is a complete processing chain for vocals, guitars, bass, or keyboards. With the DSP version in an Apollo Unison slot, supported preamp controls interact with the interface hardware; that hardware integration is not a feature of ordinary inserts or the native version.
Use Low/High Gain and preamp Level for character, then the clean Master Output for final loudness. Distinguishing these stages prevents a level correction from unintentionally changing the tube saturation.
Source: Manual - Operational Overview; Unison Integration; Century Tube Channel Strip Controls.
The Controls
Tube Preamp
- Gain Low/High: Changes the gain range and saturation behavior. Low suits stronger sources; High accommodates lower-output microphones.
- Input Select: Switches Mic/Line operation. Switching can produce a substantial level change.
- High Pass Filter: Removes low-frequency energy below an 80 Hz corner with an 18 dB/octave slope.
- Polarity: Inverts the incoming signal's polarity for alignment with related tracks or microphones.
- Pad: Attenuates the Mic input by 20 dB; it is unavailable for Line and Hi-Z inputs.
- Level: Drives the preamp output stage. Higher settings increase tube coloration as well as level.
- OL LEDs: Show overload at the preamp input and output, helping distinguish where clipping occurs.
Equalizer
- Low: Boosts or cuts the 110 Hz low shelf by up to 12 dB.
- Freq and Mid: Choose a midrange center from 300 Hz to 7.2 kHz, then boost or cut by up to 12 dB. The response changes with gain.
- High: Boosts or cuts the 10 kHz high shelf by up to 12 dB.
- Out/In: Bypasses or enables just the EQ.
Opto Leveler
Compression increases optical gain reduction. The circuit provides automatic gain compensation, so use the Gain Reduction Meter as well as your ears to judge how firmly it is controlling the source. There are no separate user attack, release, or ratio knobs.
The leveler's Out/In switch allows a direct comparison without disabling the preamp or EQ.
Master
Output is clean digital gain from silence to +12 dB. Use it to level-match the processed result without changing the preamp's drive. The VU Meter shows output level, and Off/On bypasses the entire strip.
Unison-specific mirrored controls and gain-stage hardware operation apply only with a compatible interface and the DSP plug-in in its dedicated Unison insert.
Source: Manual - Operational Overview; Unison Integration; Century Tube Channel Strip Controls.