Mercury EQ-H1 MKIV is a mono passive tube program equalizer based on the Pultec EQH circuit. What separates it from the related EQ-P1 is the make-up gain stage: here it runs single-ended, which you hear as a different, more forward kind of saturation.
An equalizer that adds something even when you boost nothing
A Pultec works differently from an EQ in a DAW: the filters are passive, so they only subtract, and the lost level is made up by a tube gain stage. It is that stage, not the curve, that adds the characteristic density — which is why the unit changes the sound even with the controls set flat.
Single-ended instead of push-pull, and what follows from it
A single-ended stage does not cancel even harmonics the way a balanced push-pull does. In practice that means more audible colour and less neutrality — exactly what you reach for a tube for on vocal midrange, on guitars and on a parallel mix bus. If you already own the EQ-P1, the EQ-H1 complements it rather than replacing it.
KEY FEATURES
- Mono tube program equalizer
- Passive circuit in Pultec EQH topology
- Single-ended gain stage
- More pronounced colour than the push-pull version
- Audible character even at flat settings
- Designed and built by Mercury Recording Equipment
TECHNICAL SPECIFICATIONS
- Type: tube program equalizer, passive filters
- Channels: 1 (mono)
- Reference circuit: Pultec EQH
- Gain stage: tube, single-ended
- Revision: MKIV
