Stax – 700T

Stax – 700T: Stax Audio of Japan was founded in 1938 to manufacture electronic equipment, and in 1959 they released the SR-1, the first electrostatic (ES) stereo, high-fidelity headphones (Stax calls them “Earspeakers”). Stax has gone through several owners and business models since then. From amplifiers to CD players to DACs, they have created it all.

Stax produced a fairly impressive line of electrostatic speakers in the 1980s that were highly regarded. Stax is now owned by a Hong Kong-based company, Edifier International Ltd, but Stax equipment is still manufactured in Japan. 

The new owners have refocused Stax solely on earphones, amplifiers/enhancers to power them, and earphone accessories.

Stax recently released two new amplifiers/energizers for electrostatic ‘phones. The SRM-700T (tube version) and SRM-700S are two amps that look almost identical (solid-state version). 

The only distinction between them is in the output stages. The “S” model employs FETs to power the ‘phones, while the “T” model employs a pair of 6SN7 dual triodes as output devices.

The two new amps resemble the older Stax amp/energizer known as the SRM-007tII on the outside. 

This amp, like the new SRM-700T, has a tube output, but in the case of the older model, the tube in question is a single 6FQ7/6CG7 dual triode (half for the right channel and half for the left).

 

Stax – 700T  Build Quality 

The build quality is good, but calling the SR-L700 Mk2 luxurious is a stretch. They’re all about functional engineering, with materials chosen for their functionality rather than their appearance or feel.

Aside from the lovely soft leather on the headband and earpads, there’s a lot more plastic than we expected. However, everything appears to be functional and saves weight over the metal alternative.

The SRM-700T energizer has a more traditional design than the headphones, but it is far from ordinary. It’s a well-made box with an immaculately finished front panel and a rather workmanlike casing, and everything feels solid and well-made. 

Just keep in mind that the unit gets quite warm after extended use, so place it somewhere with plenty of ventilation.

This product is available in two variations from Stax. There’s this one, which has a hybrid circuit with a low noise dual FET on the input and a pair of 6SN7GTB valves in the output stage. 

Then there’s its sibling, the identically priced SRM-700S, which replaces the valves in the output stage with JFETs.

The Stax – 700T has two inputs: balanced XLR and standard RCA, which are switched by a rotary dial on the back panel. However, moving this control to the front would probably make more sense.

 

High-Quality Sound  for optimum Comfort  

The consistency of STAX’s ear speakers and their ability to render music transparently, regardless of genre or venue—small studio, cathedral roots, orchestral hall, etc.—is unrivaled.

This means you’ll be able to see deeply into and across the soundstage, where you’ll find undiscovered nuance, oceans of microscopic detail and cues, and, as a result, a fantastic listening experience. 

There’s the blistering transient speed that electrostatics are known for, as well as the incredible realism that emerges track after track as a result of their collective characteristics.

The STAX SRM-700T, accompanied by various STAX ear speakers—STAX SR-L700MkII, SR-007A, and SR-009S—embodied sublime “MFEO”—Made for Each Other—synergy, which improves noticeably as one climbs the STAX ear speaker line.

To those who haven’t heard a STAX electrostatic ear speaker and a STAX electrostatic energizer (amplifier) together. Any of the combinations would be a shocking revelation. Again, if you enjoy music, this is a must-do on your bucket list.

The Stax – 700T worked particularly well with the Border Patrol SE-i, producing incredibly beautiful music reminiscent of golden, sunlit dusk while also bringing previously unlistenable media to life. 

The AudioNet DNP, with its neutrality and speed, weight, and propulsive energy. Allowed the duo to ride dynamic shifts as if they were saddled and bridled.

The Mola Mola Tambaqui brought it all together with the STAX SRM-700T, resulting in incredible naturalness and transparency. This trio acted more as a time and space machine, transporting this listener with supreme ease and beauty from venue to venue.

 

Last Thought about Stax  700T

This Stax 700T pairing is breathtaking in so many ways. An incredible performer that outperforms its competitors in terms of naturalness and resolution.

The electrostatic technology that gives it so many advantages has some flaws. Allowing traditional competitors to gain ground in other areas. But that doesn’t change the fact that, with the right recording. This Stax SR-L700 Mk2/SRM-700T combo can be nothing short of magical.

 

Stax  700T Specification 

 

• 6SN7 achieves a highly transparent sound
• Non-inductive winding resistors with the least inductance
• High-definition film capacitors
• Hand-selected matching FET
• EMI shielded volume control
• Volume control bypass switching
• Switchable RCA and XLR inputs. RCA parallel out.
• Features newly developed large-sized aluminum insulators, combined with new vibration-proof material plus high frictional coefficient.
• Type: FET input + vacuum tube output hybrid DC amplification driver unit
• Vacuum tube: 6SN7 x2
• Frequency response: DC – 100 kHz (with SR-009S)
• Gain: 60dB
• Harmonic distortion: 0.01% or less (1 kHz / 100 V rms output)
• Input impedance: 50 kΩ (RCA), 50 kΩx 2 (XLR)
• Maximum output voltage: 340 V rms (1 kHz)
• Bias voltage: PRO 580 V
• Operating temperature / humidity: 0 to 35 degrees C / less than 90% (non condensing)
• Input terminal: RCA x 1, XLR x 1
• Output: RCA parallel output terminal
• Power consumption: 54 W
• Dimension: 240 W x 103 H x 393 D mm (maximum protruding portion included)
• Weight: 5.7 kg