Audiotales 1954 EQ

Audiotales 1954 EQ is a fully passive mastering equalizer with no active stages and no power supply. The circuit is built around custom-wound Lundahl transformers chosen to contribute as little coloration of their own as possible.

The midrange the 1951 does not reach

The 1951 works at the extremes of the spectrum and leaves a gap between 150 Hz and 6 kHz open, which is precisely where vocals, snare and guitars sit. The 1954 fills that range. A Varishelf function on the low and low-mid bands changes the slope shape, so the same move can be made broad or narrow without switching to another unit.

Equalization with no level loss and no mains

A typical passive equalizer attenuates everything and needs a make-up stage that adds noise. Here there is no level loss at all, and the absence of a power supply means no mains hum and no parameter drift with temperature. The Coloreq section handles progressive coloration, the Loudness section shapes both ends of the spectrum from a single control, and the Dual RIAA curves provide split tilt equalization. Every control is detented, so settings recall exactly.

KEY FEATURES

• Fully passive design with no active stages and no power supply
• No volume loss when equalizing
• Custom-wound Lundahl transformers
• Varishelf function on the low and low-mid bands
• Coloreq section for progressive tonal coloration
• Loudness section operated from a single control
• Dual RIAA curves for split tilt equalization
• Detented controls with a switchable front-panel matrix

TECHNICAL SPECIFICATIONS

• Type: passive mastering equalizer
• Active stages: none
• Power: not required
• Volume loss: none
• Transformers: custom-wound Lundahl
• Sections: Loudness, Varishelf, Coloreq, Dual RIAA
• Controls: detented, with a switchable front-panel matrix
• Operating range: midrange complementing the 1951
• Manufacturing: hand-assembled in France