The JBL/UREI Model 5547A is a vintage mono 30-band (1/3 octave) graphic equalizer produced in the late 1980s. Prized for its high-performance analog circuitry, it was designed primarily for live sound reinforcement (FOH/monitors) and room tuning, though it is occasionally found in studio racks for musical tone-shaping. Unlike standard graphic equalizers of its era that used cheap op-amp synthetic inductors, the 5547A utilizes custom, low-noise Class-A discrete hybrid microcircuits to mimic passive inductors, providing a smooth and musical sound. [1, 2, 3, 4, 5, 6]Key Specifications

• Bands: 30 bands on standard ISO 1/3-octave center frequencies ranging from 25 Hz to 20 kHz.
• Boost/Cut Range: ±12 dB per band.
• End-Cut Filters: Tunable High-Pass Filter (20 Hz to 250 Hz at 12 dB/octave) and Tunable Low-Pass Filter (3.5 kHz to 20 kHz, switchable between 6 dB or 12 dB/octave).
• I/O Connections: Rear-panel options include balanced XLR, 1/4" phone jacks, and a barrier strip terminal.
• Impedance: 20k Ω balanced input, 600 Ω transformer-isolated output.
• Max Level: +22 dBu max input and +22 dBm max power outpu