Tegeler Audio Classic Equalizer EQP-1

The Tegeler Audio Classic Equalizer EQP-1 is a passive tube equalizer built after the circuit topology of vintage Pultec-style designs, using passive capacitors and inductors in the EQ section to produce the smooth, musical frequency curves that have made this circuit approach a standard in professional mixing and mastering for decades. Three independent sections—a low shelf for boost and cut, a variable-bandwidth peak for high boost, and a high-frequency shelf for attenuation—cover the most commonly needed tonal adjustments on program material, buses, and individual instruments. A tube stage and high-quality input and output transformers are always active in the signal path, adding density, low-end definition, and a pleasant rounding of the high frequencies regardless of whether any EQ bands are engaged. For Los Angeles mixing and mastering engineers seeking the characteristic warmth and presence of a passive tube equalizer, the Classic Equalizer EQP-1 delivers it in a 2U format built around one of the most enduringly musical filter circuit topologies in audio history.

Key Features

• Passive EQ circuit — capacitors and inductors throughout — the EQ section uses passive components rather than active amplification, producing the gentle, asymmetrical boost and cut curves characteristic of vintage Pultec-style designs and responsible for the EQP-1’s smooth, non-fatiguing sound on voices, instruments, and full program material.
• Three-section EQ architecture — a low shelf section handles bass boost and cut with four selectable frequency points; a variable-bandwidth high boost section covers nine selectable frequencies with an adjustable bandwidth control for shaping presence and air; and a separate high attenuation section provides high-frequency shelf rolloff at three positions.
• Tube stage always active in the signal path — the tube amplifier stage and input/output transformers are engaged whenever the unit is in circuit, contributing additional density, low-end transparency, and rounded highs to the signal even when all EQ bands are set flat.
• Input and output transformers — high-quality transformers at both the input and output contribute the same low-end tightening and high-frequency smoothing found across the Tegeler Audio line, adding a layer of harmonic character beyond what the EQ bands alone provide.
• Bypass switch — a dedicated bypass switch removes the unit completely from the signal path for fast, direct comparison of processed and unprocessed signals.
• Internal power supply — the EQP-1 is self-powered, simplifying rack integration without requiring an external supply.

Specifications

• Format: 2U rackmount
• Dimensions: 2U × 19.02″ W × 9.84″ D (H: 3.47″)
• Frequency Response: 20 Hz–22 kHz
• EQ — Low Boost/Cut (Low Shelf): 20 / 30 / 60 / 100 Hz
• EQ — High Boost (Variable-Bandwidth Peak): 3 / 4 / 5 / 6 / 8 / 10 / 12 / 16 / 20 kHz
• EQ — High Attenuation (High Shelf): 5 / 10 / 20 kHz
• Maximum Input Level: +20 dBu
• Input Impedance: ≥2.4 kΩ
• Output Impedance: <600 Ω
• Maximum Output Level: +22 dBu
• Dynamic Range: ≥95 dB
• Voltage: 230 V~/50 Hz or 115 V~/60 Hz
• Fuse: 500 mA slow-blow
• Maximum Power Consumption: <25 W