Tegeler Audio Vari Tube Recording Channel

The Tegeler Audio Vari Tube Recording Channel (VTRC) is a 3U Class-A channel strip built around three triode tubes, combining a variable-character tube microphone preamp, a passive Pultec-style equalizer, and a dual compressor section—optical and Vari-Mu—in a single all-transformer, stepped-control signal path. The preamp’s tonal character is continuously adjustable from clean and transparent to harmonically rich and full, and the passive EQ offers a wide range of switchable boost and cut frequencies suited to vocals, instruments, and any source requiring detailed tonal shaping. Unlike channel strips limited to a single compressor type, the VTRC runs its optical and Vari-Mu compressors simultaneously, with the EQ positionable before or after compression—or routed into the compressor’s sidechain for frequency-dependent compression and de-essing. A dedicated line input with its own transformer extends the VTRC to post-recording refinement, and two units can be linked for stereo operation, making it a comprehensive tracking and processing tool for Los Angeles studio engineers and home studio professionals alike.

Key Features

• Variable-character tube microphone preamp — the preamp’s character is continuously adjustable from clean and transparent to fat and saturated, allowing engineers to tailor the tonal color of the recording at the source rather than in post. Includes true 48V phantom power, a phase switch, and a high-impedance instrument input (100 kΩ) for direct tracking.
• Passive Pultec-style equalizer — covers low-cut (80–160 Hz), low-mid boost (80 Hz–1 kHz), mid-cut (200 Hz–7 kHz), and high boost (1.5–24 kHz), providing the soft, musical curves associated with passive transformer-based EQ designs.
• Dual compressor section — optical and Vari-Mu, simultaneously operable — the optical compressor uses an LED-and-resistor circuit to produce open, transparent level control with minimal impact on micro-dynamics; the Vari-Mu stage acts on tube gain directly for a denser, more present sound. Both can run in tandem for a combined compression character.
• Switchable EQ and compressor routing — the EQ can be positioned before or after the compressor in the signal chain, or switched into the compressor’s sidechain for frequency-dependent compression and de-essing without affecting the main signal path.
• Dedicated line input with separate line transformer — a discrete line-level input bypasses the microphone input transformer and routes signal through a transformer designed specifically for line-level signals, making the full VTRC signal chain—preamp, EQ, and compressor—available for processing already-recorded material.
• Stereo linking — two VTRC units can be linked for stereo operation, extending the channel strip to full stereo bus and stereo tracking applications.
• Soft-knee, program-adaptive compression — both compressor stages use soft-knee curves and program-adaptive attack and release timing, keeping compression musical and transparent across a wide range of source material.
• Class-A circuit, all stepped potentiometers — the fully Class-A signal path runs through transformer-balanced inputs and output, and every control uses stepped potentiometers for reliable session recall.
• Internal power supply with toroidal transformer — the VTRC’s power supply is self-contained, reducing external noise and simplifying rack integration.

Specifications

• Format: 3U rackmount
• Dimensions: 3U × 19.02″ W × 9.84″ D (H: 5.20″)
• Circuit: Class-A, 3 triodes
• Frequency Response: 20 Hz–22 kHz
• Maximum Mic Input Level: +12 dBu
• Maximum Line Input Level: +20 dBu
• Maximum Instrument Input Level: +6 dBu
• Line Input Impedance: ≥2.4 kΩ
• Instrument Input Impedance: ≥100 kΩ
• Output Impedance: <600 Ω
• Maximum Output Level: +24 dBu
• Dynamic Range: ≥95 dB
• EQ — Low-Cut: 80–160 Hz
• EQ — Low-Mid Boost: 80 / 120 / 200 / 300 / 500 / 700 / 1,000 Hz
• EQ — Mid-Cut: 200 / 300 / 500 / 700 Hz, 1 / 1.5 / 2 / 3 / 4 / 5 / 7 kHz
• EQ — High Boost: 1.5 / 2 / 3 / 4 / 5 / 7 / 10 / 12 / 16 / 20 / 24 kHz
• Voltage: 230 V~/50 Hz or 115 V~/60 Hz
• Fuse: 500 mA slow-blow
• Maximum Power Consumption: <25 W