Pultec EQH-2 Program Equalizer

Pultec EQH-2 Program Equalizer appeared in 1956 as a compact alternative to the 3U EQP-1 and remains the simplest unit in the tube Pultec line. Its low-frequency curves are identical to the EQP-1A and its high peak centres are comparable. The difference lies in what the EQH-2 deliberately leaves out: bandwidth adjustment and a choice of high-frequency attenuation corner. Instead of the wide-bandwidth amplifier of the 1A family, it uses the same minimalist class A stage found in the MEQ-5.

Fewer knobs, faster decisions

Bandwidth is fixed at the factory and high attenuation works on a fixed 10 kHz corner. In practice that leaves three decisions instead of five: which low centre, how much boost and cut, and which high peak centre. On a tracking session, where the equalizer sits in an insert and the sound has to be found in a handful of moves, fewer variables genuinely shortens the work. Recall benefits too: fewer settings mean fewer things to write down when the session has to be rebuilt.

A shorter signal path and a more transparent sound

The EQH-2 uses the same minimalist class A output stage as the MEQ-5, on 12AX7, 6AQ5 and 6X4 tubes, with 600 Ohm transformers at input and output. A number of engineers, among them Dave Cobb and Michael Dumas, consider it more transparent than the EQP-1A and EQP-1A3. So the choice is a deliberate one between the character of the 1A family's wide-bandwidth amp and a lighter footprint on the signal. The low section keeps simultaneous boost up to 13.5 dB and cut up to 17.5 dB at the same frequency, the setting people buy a Pultec for in the first place.

KEY FEATURES

• Passive equalization network with a minimalist class A tube stage
• The same output amplifier as the MEQ-5, regarded as more transparent than the 1A family
• Low-frequency curves identical to the EQP-1A: 20, 30, 60 and 100 Hz
• Simultaneous low-frequency boost and attenuation at the same frequency
• Five high-frequency peak centres at fixed bandwidth
• High-frequency attenuation on a fixed 10 kHz corner
• Simplified panel with fewer settings to recall
• 600 Ohm input and output transformers

TECHNICAL SPECIFICATIONS

• Type: passive program equalizer with tube line amplifier
• 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, 5, 8, 10, 12 kHz, 0-18 dB, fixed bandwidth
• High shelf attenuation: 10 kHz, 0-16 dB
• Input transformer: 600 Ohms
• Output transformer: 600 Ohms
• Noise: below -75 dBm
• Distortion: 0.15% max at +10 dBm into 600 Ohms
• Amplifier response: 20 Hz to 20 kHz, +0 / -1 dB ref 1 kHz
• Tubes: 12AX7, 6AQ5, 6X4 (one each)