STAX SRM-700T

Pre owned. In excellent condition. Free from any visible signs of wear. Supplied with manual, accessory and original packaging.

Hybrid amplifier for electrostatic headphones that incorporates some of the design principles of the flagship SRM-T8000, combining a solid-state driver stage with a vacuum tube output stage. This configuration integrates the precision and speed of semiconductor devices with the tonal characteristics associated with thermionic technology within the same circuit.

The input stage uses a pair of low-noise dual FETs, custom-designed to STAX specifications, which amplify and drive the signal while keeping noise levels low. The output stage uses 6SN7GT vacuum tubes, derived from the 6FQ7 family and selected for their linearity and drive capabilities. The use of vacuum tubes in the final stage contributes to a warm tonal character and a spacious presentation, while the FET stage provides control and precision.

The load section uses VISHAY non-inductively wound resistors, selected for their behavior in audio circuits. The choice of these components is part of a design aimed at maintaining a high circuit slew rate while minimizing unwanted effects introduced by passive components.

The combination of low-noise FETs and 6SN7GT vacuum tubes allows the SRM-700T to combine dynamics and precision with a warmer and more spacious presentation. The result is an amplifier dedicated to STAX electrostatic headphones that implements hybrid technology through a precise division of functions between the solid-state and vacuum tube stages.

Technical specifications:

• Type: hybrid DC driver unit with FET input and vacuum tube output
• Vacuum tubes: 2 x 6SN7
• Frequency response: DC–100 kHz with one STAX SR-009S
• Gain: 60 dB
• Harmonic distortion: ≤0.01% (1 kHz, 100 Vrms output)
• Input impedance: 50 kΩ (RCA); 50 kΩ x 2 (XLR)
• Maximum output voltage: 340 Vrms (1 kHz)
• Bias voltage: PRO 580 V
• Operating temperature/humidity: 0–35 °C; <90%, non-condensing
• Inputs: 1 x RCA; 1 x XLR
• Output: RCA parallel output terminal
• Power consumption: 54 W
• Dimensions (WxHxD): 240 x 103 x 393 mm (including protruding parts)
• Weight: 5.7 kg