Heritage Audio 73 EQ Jr., 3-Band 500 Series EQ Module, Carnhill transformers, Input impedance: 10 kOhm, Output impedance: Less than 75 Ohm, +6 to -20 dB Class A Line preamp, HF: +/- 16 dB shelving (10, 12, 16 or 20 kHz adjustable), LF +/- 16 dB shelving (35, 60, 110 or 220 Hz adjustable), MF +/- 18 dB peak (adjustable centre frequency 0.36, 0.7, 1.6, 3.2, 4.8 and 7.2 kHz), Fixed Q, Max. gain: 6 dB, Design: Module 500