Stax
STAX SRM-700S
Best driver for audiophiles seeking pure, high-fidelity electrostatic sound.
The STAX SRM-700S is a high-fidelity electrostatic headphone driver unit, featuring a fully discrete dual FET configuration. Its J-FET output and large emitter follower circuit ensure exceptionally low noise levels, allowing for precise music reproduction without losing any detail. This desktop unit is designed for audiophiles seeking the purest sound experience. It offers a wide frequency response and a robust bias voltage, making it a powerful companion for high-end electrostatic headphones.
$3400.00
More SRM Options
Owner Satisfaction
4.5
/ 5
Category Rank
387
/ 733
#387 in Headphone Amplifiers
Price vs Category Average
+143%
Above average
Type
DC amplification driver unit with all-stage FET configuration
/ DC amplification driver unit with all-stage FET configuration
Who it's for
- Audiophiles seeking absolute transparency and microscopic detail in their music
- Listeners wanting consistent, maintenance-free performance from their electrostatic gear
- System builders needing versatile connectivity for high-end audio components
Who should skip it
- Budget-conscious buyers looking for entry-level or mid-range audio solutions
- Collectors who own dynamic or planar magnetic headphone collections
- Users with limited desk space or cramped listening environments
Performance breakdown
Signal Clarity
The discrete FET design eliminates noise for a pristine, transparent soundstage.
Dynamic Range
Captures the full spectrum from deep lows to ultra-high frequency details.
Build Integrity
Robust construction ensures long-term stability for high-end electrostatic listening setups.
Output Precision
High bias voltage delivers the exact power required for electrostatic driver performance.
Connectivity Versatility
Balanced XLR and RCA inputs accommodate a wide range of source equipment.
Desktop Footprint
Compact enough for most desks while maintaining necessary thermal management space.
Key Specs
Type
DC amplification driver unit with all-stage FET configuration
Frequency Response
DC – 100 kHz
Gain
60dB
Harmonic Distortion
0.01% or less
Input Impedance
50 kΩ
Maximum Output Voltage
450 Vrms
Bias Voltage
PRO 580 V
Power Consumption
46W
Features
- Fully discrete dual FET configuration for exceptional audio quality
- Low noise floor thanks to J-FET output and large emitter follower circuit
- Precise music reproduction that captures every detail
- Wide frequency response from DC to 100 kHz
- High bias voltage (PRO 580V) for optimal electrostatic headphone performance
- Multiple input options including RCA and XLR
- Compact desktop design
What customers say
Customers consistently laud the STAX SRM 700S for its exceptional sound quality and robust build. Many highlight its remarkable clarity, detail, and expansive soundstage when paired with Stax electrostatic headphones, significantly elevating the listening experience. Users appreciate the amplifier's reliable performance and the premium feel of its construction, reflecting Stax's reputation for high end audio. While it represents a significant investment, enthusiasts often consider its sonic performance and enduring quality to justify the cost, viewing it as a cornerstone for their electrostatic systems.
Know before you buy
This driver unit is specifically engineered for STAX electrostatic headphones. It is not compatible with standard dynamic or planar magnetic headphones.
Yes, the SRM-700S features both RCA and XLR inputs. You can switch between these sources using the input selector on the front panel.
Like many high-end audio components, the discrete FET circuitry performs best once it reaches a stable operating temperature. While it will work immediately, you may notice the soundstage and detail resolve more fully after 15 to 20 minutes of use.
The J-FET configuration is chosen for its ability to maintain an exceptionally low noise floor. This ensures that subtle details and micro-dynamics in your music remain clear and undistorted, even at lower listening volumes.
Yes, the SRM-700S provides the standard 580V PRO bias voltage. It is fully compatible with all modern STAX earspeakers that utilize the 5-pin PRO connector.
The unit measures 240mm wide by 393mm deep. You should also ensure there is a few inches of clearance around the top and sides to allow for proper heat dissipation during operation.
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