Hi-fi headphone or earphone STAX Pack SR-307 + SRM-353X

Headphone Preamplifiers: SRM-353X

The SRM-353X is a specific headphone amplifier (driver), designed especially to optimally power STAX electrostatic headphones. Strictly selected, audiophile-grade audio components improve the sound signature, and a new detailed circuit design study has further extended the bandwidth. XLR input terminals allow connection to the balanced inputs of audio devices to benefit from their superior performance.

The first stage uses dual low-noise FET (field effect) transistors, and an improved direct-coupled DC class A configuration on all stages, without capacitor coupling, resulting in a natural sound signature with a wealth of information. The use of an improved emitter-follower circuit for the output stage enables a wider bandwidth sound reproduction, allowing for more extended high-frequency dynamics and enhanced sound quality. An XLR balanced input is provided in addition to the RCA input jacks, allowing connection to a wider range of audio devices.

The driver features a custom-designed coaxial volume control. It has the superb usual STAX housing made of non-magnetic aluminum alloy. Low-aging components have been custom selected for their characteristics and performance in terms of sound signature.

Headphones: SR-307

These audiophile headphones use electrostatic panel technology and require a compatible amplifier. Thanks to the large emissive surface, the listener is immersed in a musical ambiance beyond comparison with traditional headphone transducers. The main characteristic of the listening experience is absolute transparency across the entire audio spectrum, as well as an absence of overhang in the bass. In a word, the listening experience is breathtaking.

The Stax SR-307 (gray) and SR-407 (brown) cannot be connected to just any headphone output and require the use of a specific amplifier, particularly due to constraints related to their impedance. These models are compatible with Stax amplifiers.

Note that the SR-407 version is a color variation and has the same characteristics, with the exception of some variations concerning the inductance and impedance of the modulation cable. The listening experience therefore differs slightly and proves to be even more spatial.

Headphone Preamplifiers: SRM-353X

Frequency response: DC to 90 kHz (with SR-L series headphones).
Maximum input level: 100mV (for 100V output).
Gain: 60dB.
Maximum total harmonic distortion: < 0.01% (with SR-L500, for 100 mVrms, at 1 kHz output).
Input impedance: 50 kOhms (RCA).
Maximum output voltage: 400 V RMS / 1 kHz.
Bias voltage: DC580 V.