The 2U (3.5" tall) EQP-1A3 is a condensed version of the 3U (5.25" high) EQP-1A. In 1971, after 10 years of EQP-1A production and due to customer demand, Gene and Ollie rearranged controls and components to reduce the height of the popular equaliser. As indicated on the original EQP-1A3 product brochures "SAME PARTS, SAME SPECS". The EQP-1A3 was the first product in the Pultec line that Pulse Techniques brought back into production and has continued to be very popular. New York City's Power Station had 24 of them in each control room! Pultec now makes them both, so you can take your pick. But be assured, they both have all that Pultec mojo that you are seeking. 20, 30, 60, 100 CPS (Hz) shelf boost, 0 - 13.5 dB 20, 30, 60, 100 CPS shelf attenuate, 0 - 17.5 dB 3, 4, 5, 8, 10, 12, 16 KCS (kHz) peak boost, 0 - 18 dB 5, 10, 20 kcs shelf attenuate, 0 - 16 dB Input Impedance: ~600 Ohms Output Impedance: ~50 Ohms Noise: 92 dB below +10 dBm Distortion: ≤ 0.15% at +10 dBm into 600 Ohms Amplifier: Flat, 20 CPS to 20 KCS, +/- 0.5 dB Tubes: 1 ea 12AU7, 12AX7, 6X4