PREAMPS/EQS/DIRECTS:

API 550A
vintage semi-parametric EQ (1974) x2

Three-band studio standard equalizers. All discrete. Selectable frequencies with 12dB of “proportional Q” gain, high and low shelving options, and high pass filter. Slightly “hard” sound, especially useful for maintaining clarity on bass-heavy instruments. These came out of a console at a PBS station.