EQP-1A
Effects by Pulse Techniques
The EQP-1A is a passive program equaliser made by Pulse Techniques, introduced in 1961. It pairs passive filter circuits with a vacuum tube makeup amplifier, and the Pultec trick of boosting and cutting the same low frequency at once is widely used on bass, kick and full mixes.
Specifications
| Type | Passive program equaliser with vacuum tube make-up amplifier |
| Controls | Low frequency selector (20/30/60/100 Hz) with boost (0 to +13.5 dB) and attenuate (0 to -17.5 dB); high boost selector (3/4/5/8/10/12/16 kHz) with boost (0 to +18 dB) and bandwidth control; high attenuate selector (5/10/20 kHz) with attenuate (0 to -16 dB); in/out bypass switch |
| Bypass | In/Out switch (EQ section bypassed; make-up amplifier remains in circuit) |
| Bands | 3 |
| Series | Pultec |
| Format | 19-inch rack, 3U |
| Dimensions | 483 x 133 x 197 mm |
| Weight | 6.8 kg |
| Power Supply | 117 V AC, 50/60 Hz |
| Power Consumption | 25W |
| Connections | Transformer-balanced input and output, 600 ohm (strappable to 250/150 ohm input, 300/150 ohm output). Originals used screw terminals; current reissues use XLR |
| Notes | All-passive LC EQ network followed by push-pull tube make-up amplifier. Tubes: 12AX7 input, 12AU7 output, 6X4 rectifier. Amplifier response flat 20 Hz to 20 kHz +/-0.5 dB. THD <= 0.15% at +10 dBm into 600 ohm. Noise 92 dB below +10 dBm. Famous Pultec trick: boosting and attenuating the same low band simultaneously gives a deep cut just above the boost peak. Designed by Eugene Shenk at Pulse Techniques Inc., Teaneck NJ; original production 1961-1971, reissued by Pulse Techniques LLC from 2000. |
