Description

This single-channel equalizer uses passive LC circuitry with class-A triode vacuum tube stages for the input and output. The tube circuitry is largely derived from the VT-1/VT-2 mic preamp design, so the equalizer has much the same sonic character as the preamps.

The LC-style passive equalization circuitry is based on the classic designs that are still the best-sounding way to achieve high-quality tonal control.

The input is line-level, transformer balanced-bridging. An active vacuum tube input section has adjustable gain to accomodate input signals as low as -10 dBm. The input transformer is made by Jensen. The output stage utilizes the same custom Jensen transformer used on the VT-1/VT-2 mic preamps.

All controls are stepped for precise repeatability and uniform matching between units. High-quality rotary switches are used with 1% metal-film resistors. All of the audio capacitors are polystyrene or polypropylene. The inductors are custom-made for us by Jensen Transformers Inc. 

The equalizer is constructed of heavy-guage aluminum, with a a 3RU (5.25 inch), 1/4-inch thick front panel, finished in D.W. Fearn red. It matches the VT-1/VT-2 series of mic preamps in appearance and construction.

Like the VT-1/VT-2 preamps, the Equalizer has been designed to provide an exceptional tool for audio professionals. The design frequencies and curves were determed by ear, after extensive listening to a variety of program material, both individual tracks and overall mixes. The result is a highly-musical equalizer with plenty of range for enhancing any track or mix.

SPECIFICATIONS

(All controls are independent and can be used in any combination)

Low Cut at 30, 40, 100, or 400 Hz, 0 to -18 dB shelving in 2 dB steps
Low Boost at 20, 40, 60, or 140 Hz, 0 to 16 dB shelving in 2 dB steps
Mid Cut at 200, 300, 400, 500, 600, or 700 Hz, 0 to -16 dB in 2 dB steps
High Boost at 1.5, 3, 4, 5, 8, 10, 12, or 16 kHz, 0 to 12 dB in 2 dB steps
High Bandwidth Q of 0.6, 0.8, 1.0, 1.4, or 1.7
High Frequency Cut at 1.5, 3.5, 8, or 28 kHz, 0 to -14 dB shelving in 2 dB steps
Gain adjustable from -9 to +9 dB, referenced to +4 dBm, in 3 dB steps

 NOTE: Frequency is specified in cycles per second (cps) or kilocycles per second (kc). These units correspond to Hz and kHz respectively. Measurements made with -50 dBm input and 50 dB gain in a 22 cps to 22 kc bandwidth. Specifications and price subject to change without notice.

Performance
(eq out)
Frequency response: +/- 0.2 dB 20 Hz to 20 kHz
THD: less than 0.06%
Signal-to-Noise: better than 80 dB