The Stax SRM-323A is an electrostatic headphone amplifier designed for driving Stax earspeakers. It features a high-voltage emitter-follower circuit that utilizes bipolar transistors in the output stage, allowing for low output impedance which enhances drivability and extends the high-frequency dynamic range. The amplifier is equipped with a power transformer similar to that used in other models to ensure robust output capabilities. It includes a simple RCA input with a parallel-out terminal for direct signal access. Additionally, the unit has two 5-pin output sockets that accommodate all pro-bias compatible earspeakers. The SRM-323A employs a double-axis volume control system that allows independent adjustment of left and right channel volumes. Specifications include a frequency response from DC to 60,000 Hz with a maximum harmonic distortion of 0.01% at 1 kHz and a rated gain of 60 dB. It has a maximum input voltage of 30V, input impedance of 50KΩ, and can output up to 400V r.m.s. The power requirements are 117V at 50/60Hz with a consumption of 30W. The unit functions effectively within a temperature range of 0 to 35°C and 90% maximum humidity without condensation. Its dimensions are 5.9 inches width, 3.9 inches height, and 14.2 inches depth, and it weighs 6.4 lbs. The amplifier is presented in a silver finish.
