Pultec EQP-500X 500 Series Program Equalizer

Pultec EQP-500X 500 Series Program Equalizer moves the signal path of the solid-state EQP-1A3-SS and EQP-1S3-SS into a 500-series module. The basis is the same proven design: a passive equalization network behind an input transformer, and a gain stage built on a genuine API 2520 opamp driving a Triad output transformer. The curve set matches the 1S3, the widest in the line, high-frequency shelf boost included.

Eight channels of Pultec in one rack

The rackmount versions take 2U per channel, so passive equalization across a whole drum section means a dozen or more rack units and a separate power supply in every box. A 500-series module occupies one slot, draws from the rack's supply, and lets you assemble a multichannel Pultec setup inside a single 3U enclosure. That changes how tracking sessions work, with passive equalization reaching several microphones at once rather than only the bus. Recording drums, a horn section or several guitars at the same time, the difference between one slot and two rack units per channel decides whether the setup is possible at all.

The full curve set with no concession to size

The smaller format does not mean a trimmed equalization section. You still get low curves at 30, 40, 70 and 100 Hz with simultaneous boost and cut, nine high peak centres from 1 to 16 kHz, shelf boost with 5 and 10 kHz corners, and shelf attenuation at 5, 10 or 20 kHz. The character of the path is the one engineers describe as punchier with a tighter low end than the tube variant. A maximum output level of +21 dBm and noise below -80 dBm match the rackmount versions exactly.

KEY FEATURES

• Passive Pultec equalization in a 500-series module
• Genuine API 2520 opamp with a Triad output transformer
• Curve set matching the EQP-1S3-SS
• High-frequency shelf boost with 5 and 10 kHz corners
• Nine high-frequency peak centres, including 1 and 2 kHz
• Simultaneous low-frequency boost and attenuation at the same frequency
• One rack slot per channel instead of 2U in the rackmount version
• Output level to +21 dBm and noise below -80 dBm

TECHNICAL SPECIFICATIONS

• Type: passive program equalizer in 500-series format, solid-state amplifier
• Gain stage: API 2520 with Triad output transformer
• Low shelf boost: 30, 40, 70, 100 Hz, 0-13.5 dB
• Low shelf attenuation: 30, 40, 70, 100 Hz, 0-17.5 dB
• High peak boost: 1, 2, 3, 4, 5, 8, 10, 12, 16 kHz, 0-18 dB
• High shelf boost: 5, 10 kHz, 0-14 dB
• High shelf attenuation: 5, 10, 20 kHz, 0-16 dB
• Input impedance: approx. 600 Ohms, output 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