STAX SRM-400S Semiconductor Driver Unit:
Legendary electrostatic headphones for audio fanatics
STAX introduces a new semiconductor driver unit SRM-400S, the successor model of the SRM-353X. STAX custom-made low noise DUAL FET is installed on First Stage. And FET is also installed on Last Stage. The characteristics of right FET and left FET are measured strictly. Selected FET are installed as well as SRM-700S. SRM-400S succeeds to the design and the manufacturing method of the high end model SRM-700S, the amplifier which FET are installed in all stages.
In addition to the conventional power transformer for the high voltage circuit, the newly designed power transformer with the winding for the low voltage circuit is installed in SRM-400S. The low voltage winding enables to improve the power efficiency and achieve further power saving and better sound quality than the conventional driver units such as SRM-353X.
The new chassis which is more rigid than the conventional model is installed. The chassis has a hybrid structure using a lot of non-magnetic aluminum and further reduces the effect of the environmental noise factors such as vibrations. The inputs are RCA and XLR, the mutual exclusion inputs. The custom made concentric dual volume knob which is common to STAX products and RCA PARALLEL OUT functions are installed same as the conventional driver units. All electric components are strictly selected considering the environment. Also the sound quality and the performance is improved. The complete DC amplifier configuration that the signal circuit includes no coupling condensers is one of the biggest traditional features.
SRM-400S takes over the high resolution sound which is unique to the semiconductor circuit and dynamic low range sound reproduction. Simultaneously, the good sound balance is further pursued than SRM-353X. From the low range to the high range, the sound of each range is well harmonized. Not only for the combination with the advanced lambda series, SRM-400S is also ideal for the upgrading from the entry level SRS-3100. This is the promising new model which covers from beginners to intermediates among the renewed driver unit lineup.
All-stage FET configuration DC amplification driver unit
Frequency response: DC – 90kHz (with one SR-L500 MK2)
Harmonic distortion: 0.01% or less (1kHz/100Vrms output)
Input impedance: 50k Ω (RCA), 50k Ω x 2 (XLR)
Maximum output voltage: 400Vrms (1kHz)
Bias voltage: DC 580V
Operating temperature / humidity: 0 to 35 degrees celsius / less than 90% (non condensing)
Input terminal: RCA x 1, XLR x 1(mutual exclusion input)
Output: RCA parallel output terminal
Power consumption: 30W
Dimension: 195 (W) x 102 (H) x 376 (D) mm (maximum protruding portion included)
In addition, a new chassis with increased rigidity compared to SRM-006tS has been adopted. The hybrid structure, which uses a lot of non-magnetic aluminium, further suppresses the effects of physical external noise such as vibrations. The inputs are RCA and XLR, the mutual exclusion inputs. The custom made concentric dual volume knob which is common to STAX products and RCA PARALLEL OUT functions are installed same as the conventional driver units. All electric components are strictly selected considering the environment. Also the sound quality and the performance is improved. The complete DC ampli er con guration that the signal circuit includes no coupling condensers is one of the biggest traditional features.
The clear and highly transparent sound, a feature of the vacuum tube circuit and the warm and wide sound texture are maintained and the thickness of the low-mid range is brushed up.
Therefore we recommend the SRM-500T in combination with the advanced lambda series earspeakers (SR-L300/SR-L500 MK2/SR-L700 MK2).
SOUND ODYSSEY BV