Tegeler Audio Classic Equalizer EQP1 Tube Dual- Mono Passive Program EQ

The Classic Equalizer EQP-1 is a passive tube program equalizer built in the lineage of the original Pultec EQP-1A, offered here in a dual-mono configuration with a fully independent control set on each of its two channels. Rather than a single shared stereo circuit, dual-mono means left and right (or two unrelated mono sources) can be voiced completely differently, which matters for mastering work where small channel-to-channel imbalances need correcting, or for tracking two unrelated instruments through the same box at once.

Its EQ network follows the same three-section logic the Pultec design made famous: a low-frequency shelf that can boost and cut at overlapping points simultaneously for that broad, non-cancelling bottom-end lift, a bandwidth-adjustable midrange/treble boost, and a separate fixed high-frequency shelf cut. All of the filtering itself is done with passive components, capacitors and inductors, which is what keeps the tone free of the harshness solid-state EQ curves can introduce at extreme settings. A tube gain stage and a pair of input/output transformers sit around that passive network, adding harmonic density and a rounder top end even when the EQ curve itself is left flat.