Pultec EQP-1A3-SS Program Equalizer

Pultec EQP-1A3-SS Program Equalizer is the EQP-1A3 with a solid-state gain stage. The front end is identical to the tube version: the same input transformer and the same passive equalization network. Only the way level is restored changes, because in place of tubes there is an API 2520 opamp driving a Triad output transformer, exactly as in the originals from the early 1970s. Pulse Techniques is the only company licensed to use genuine API 2520 opamps.

A shorter attack on kick, bass and piano

Engineers describe this version as punchier, with a tighter low end than the tube variant, and that is not a matter of a louder sound but of how the gain stage behaves on transients. On kick, snare, bass and piano it means the attack survives a simultaneous lift at 60 or 100 Hz, so the bottom grows while the hit stays defined. Some rooms keep both variants and reach for the tube version on vocals and buses, the solid-state one on the rhythm section. Output headroom runs to +21 dBm with noise below -80 dBm, so the unit takes hot insert levels without careful gain matching.

The same passive network, a different output stage

The curves are identical to the tube EQP-1A3, including simultaneous low boost and attenuation at the same frequency. Up to 13.5 dB of boost at 60 Hz against up to 17.5 dB of cut on the same setting produces a bottom with mass and a cleared band directly above it. The high section offers seven peak centres from 3 to 16 kHz with a bandwidth control, plus separate shelf attenuation at 5, 10 or 20 kHz. This same circuit forms the core of the company's 500-series modules, so choosing between versions is a decision about gain-stage character, not about equalization capability.

KEY FEATURES

• EQP-1A3 passive equalization network with a solid-state gain stage
• Genuine API 2520 opamp with a Triad output transformer
• The only company licensed to use genuine API 2520 opamps
• Tighter low end and more defined attack than the tube variant
• Simultaneous low-frequency boost and attenuation at the same frequency
• Seven high-frequency peak centres from 3 to 16 kHz with bandwidth control
• Output level to +21 dBm and noise below -80 dBm
• The same circuit that forms the core of the 500-series modules

TECHNICAL SPECIFICATIONS

• Type: passive program equalizer with solid-state line amplifier
• Gain stage: API 2520 with Triad output transformer
• Low shelf boost: 20, 30, 60, 100 Hz, 0-13.5 dB
• Low shelf attenuation: 20, 30, 60, 100 Hz, 0-17.5 dB
• High peak boost: 3, 4, 5, 8, 10, 12, 16 kHz, 0-18 dB
• High shelf attenuation: 5, 10, 20 kHz, 0-16 dB
• Input impedance: approx. 600 Ohms
• Output impedance: approx. 50 Ohms
• Noise: below -80 dBm
• Distortion: 0.15% max at 10 dBm into 600 Ohms
• Amplifier response: 20 Hz to 20 kHz, +0 / -1 dB ref 1 kHz, transformers included
• Maximum output level: +21 dBm