STAX SRM-700T Electrostatic Ear speaker Driver

After reviewing the extremely impressive SRM-700S driver, STAX have sent me the SRM-700T to see how I like the tube variant of this driver.

STAX have not paid me to write this article.
Although The Audiophile Cafe is sponsored by STAX, the views and thoughts in this publication are my own unbiased opinion.
Audrey and Kay have been most gracious, kind and patient with me and I would like to personally thank them both.

The STAX SRM-700T currently retails at $3,400 at the time of this article.

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Review equipment & software:
STAX SR-009.
Musician Audio Pegasus.
MacBook Pro Retina 15″.
Qobuz Studio Premier.
KECES Audio ePhono.
KECES Audio ePower.
Technics SL1200 MKII.
Ortofon Quintet Red.
Audiowalle TP1000 mains conditioners.

Interconnects and mains cables supplied by our sponsors AF Audio & Custom Cans.
USB cable is a Crime Audio Snotora in pure silver.


Jean Michel Jarre – Les Chants Magnetiques. ( Magnetic Fields )
Jean Michel Jarre – Revolutions.
Jean Michel Jarre – Equinox. ( 180 gram )
Jean Michel Jarre – The Concerts In China.
Depeche Mode – Violator. ( 180 gram )
Pink Floyd – The Wall. ( 180 gram )
Tears For Fears – Songs From The Big Chair.
Gustav Mahler – Symphony No.5.
Mikaela Davis – Delivery. ( HI-RES / 48.0 kHz )
Lissie – Thank You To The Flowers. ( Redbook 16bit / 44.1kHz )
Chris Rea – ERA 1. ( HI-RES / 96.0 kHz )
Fleetwood Mac – Audiophile Collection. ( Redbook 16bit / 44.1kHz )
Mastodon – Once More Around The Sun. ( Redbook 16bit / 44.1kHz )
Kylesa – Static Tensions ( Redbook 16bit / 44.1kHz )
The Audiophile Cafe Demo playlist: ( mixed file formats )

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The Audiophile Cafe readers can receive 1 month’s free subscription to Studio, which allows you to listen to Qobuz’s entire music library in Hi-Res and CD quality. 
Please note: Existing Studio subscribers need to unsubscribe first before activating the gift. 
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What’s in the box:
1x STAX SRM-700T electrostatic ear speaker driver.
1x Mains cable.
1x Stereo RCA interconnect.


  • 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 aluminium 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

Build and finish:
I’ve had 4 STAX electrostatic drivers come through The Audiophile Cafe now and the first thing that stands out is the quality control.
Each unit has been flawless in its build and high quality finish.
The SRM-700T is no different. The 700t is identical to the 700S in every way, aside from the domed vents on the roof for the 6SN7 tubes and the circuitry in relation to said tubes.
Everything that was so right about the SRM-700S can be found in the SRM-700T, from the silky smooth volume and balance knob, firm and solid switches, through to the solid, heavy, yet subtle, aesthetically pleasing front panel and luxurious finish.
The rear panel is a carbon copy. Same Balanced input and RCA stereo input, parallel RCA stereo output, input selector and volume control selector. And the same premium quality seen before is evident in this unit.

Like its solid state sibling STAX have made a point of making the markings and instructions on the unit easy to understand and follow.
I’m won’t open the unit up as I’m not qualified to do so, however you can see from the info and images on STAX’s website that they use only the highest quality parts and the final assembly is spot on.
STAX have knocked it out of the ballpark. Again.

Thanks to the easy to understand rear panel and clearly marked front panel, the SRM-700T is a breeze to hook up.
Simply choose the way you want to hook up and if you want to control the volume with the unit itself or externally from a pre-amp or DAC that has volume control.
In my case, this time around I’m using a DAC that doesn’t have a pre-amp built in so I’ve set it up so I use the STAX SRM-700T’s onboard volume control.
Plug everything in, power up and you’re done.
Bear in mind, unlike the 700S, the 700T has a short warm up sequence. Indicated by an amber flashing power LED when you initially turn the driver on.

The SRM-700T is quiet with an audibly silent signal.
The soundstage is spacious and has an astonishing level of headroom.
Isolation, phenomenal. Offering a tremendous image with super-sharp separation of instruments.
The SRM-700T presents a strong, large sound.
Bass hits with finesse and authority.
The 700T has a warmth to it, yet without sounding dark or muddy.
Low sweeping bass sounds sublime and the bass to mid bass frequencies are punchy & detailed.
The midrange lends itself to a smooth, airy presentation, offering a very organic sound.
Vocals, wind and string instruments are easy to listen to, however there is also a liveliness in the mix that balances things perfectly.
And then we have the high frequencies…
I’m one of those audiophiles that likes a fair amount of top end sparkle, and boy oh boy does the 700T deliver. It delivers a forward, crystal clear sound that doesn’t roll off, yet does this without going too far.
Not often does a ear speaker driver or headphone amplifier paired with the right ear speakers or headphones give me the same enjoyment I get when listening to a high end amp & pair of speakers sporting ribbon tweeters.
The 700T paired with the SR-009 manages exactly that. Paired with the SR-L300 it’s not far off, however, we do begin to notice the highs sounding a touch rolled off at the very top. But not by much.

Digital & analogue sources alike, the SRM-700T with the SR-009 envelope you in the most exotic listening experience.

I can’t quite believe there are more expensive drivers that claim to offer superiority over this level of product.

Final thoughts:
This was an interesting review. I have already reviewed the 700T’s sibling, the 700S.
I wondered what the Tubes on the output stage would bring to the table, and I was not disappointed!
STAX have been around for a long time and it shows. Their craftsmanship, attention to detail and final product is without a doubt some of the best home audio gear on the market.
Now I’m truly diving into the realm of electrostatic gear, it’s difficult to go back to regular headphones and in this case, lower end electrostatic drivers or ear speakers.
I didn’t think I would see myself writing that, but here we are.
$7,319 is a lot of money, ( includes the cost of an extension cable ) so this won’t be in every audiophiles sights.
However, If you have the funds and are pondering an electrostatic system, please do yourself a favour and take the plunge with the SRM-700T and SR-009.
You will not regret it. In my honest opinion, it’s worth every dollar!

A massive thanks to Kay and Audrey at STAX for being extremely patient with me and as always being the super-supportive people that they are.

Huge thanks to my readers! Without you none of this would be worth it.
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The Audiophile Cafe is sponsored by a few brands and start-ups and today I’d like to thank Custom Cans and AFAudio for supplying all of the cables that connect all of the dots and allow me to take the connections out of the process.
Look out for some articles in the near future about both!