STAX SRM-400S Electrostatic Headphone Amplifier

STAX is proud to introduce a new semiconductor driver unit SRM-400S as the successor model of SRM-353X. A STAX custom-made low noise DUAL FET is installed on First Stage and additional FETs are also installed on last stage. SRM-400S follows the design and the manufacturing method of the high end model SRM-700S, in which the amplifier high quality FETs are installed in all stages. The characteristics of the right and left FETs are measured strictly and the selected FETs installed in 400S are also featured in SRM-700S. In addition to the conventional power transformer for the high voltage circuit, the newly designed power transformer with winding for a low voltage circuit is installed in SRM-400S. The low voltage winding enables to improve the power efficiency and achieves further power saving and better sound quality than what was featured in older driver units such as SRM-353X. The new chassis which is more rigid than the conventional model is installed. The chassis has a hybrid st