20 December, 2016

Stax SRS-2170

Review: Stax SRS-2170 System
Headphone Talk VII: Electrostatic Headphones
Letter from NYC (55) 2016 (11)

My attitude towards Headphone is described in Headphone Talk I

As a long-time audiophile, I am simultaneously amazed, alarmed and sometimes amused or even dismayed by the exponential growth of headphones, headphone amps and so-called "head-fi" sites. The reasons are too numerous, so I shall leave that for a planned "Hi-Fi Basics" article.

Suffice to say, I do have some rather peripheral interest in headphones, and own several respectable headphones (Audio Technica ATH-AD700, Grado SR80e, Sennheiser HD-600 and now Stax SRS-2170) and headphone amps (listening experience of my Meier Audio Corda SwingPro-ject Headbox II and the amazing bargain Micromega Myzic, which I have yet to write about). That is not all: some of my preamps have excellent headphone outputs (certainly not the usual value added feature). Both my Nagra PL-P (listening notes here) and Manley 300B preamp (here) drive headphones in the best way possible, i.e. through dedicated transformers. I doubt most current headphone amps costing into the thousands can beat those two.

This surprises me: only after researching my own blog did I find out I have actually written on quite a few headphone and headphone amps!

The Best Earphones? Best du jour?
These days, new technologies are being used to make earphones of all kinds, and reviews are all over the audio websites and magazines. Planar magnetic earphones (led by HiFiMan, Audeze and now, Oppo) are all the rage. Each is touted to be better than the last, and a breakthrough in sound. Is that truly so? I'd reckon, no.

Even my friend shidi Andrew asked me whether he should get a pair of planars. My answer to him is basically encoded below.

Electrostatic Headphones in General
  • Power Supply Electrostatics, whether loudspeakers or earphones, have the inherent disadvantage of having to be tethered to a power supply. So the usual headphone amps and outputs cannot be used with an ESL headphone. However, as I note there is now self-biasing ESL technology (no power supply needed) used for ESL supertweeters (the Enigmacoustics Sopraninos are currently the darling of the audio press), I harbour hope perhaps this technology can be used in headphones in the near future to free the ESL from its power supply.
  • Adaptors There are adaptors which both provide the connection and power supply for ESL headphones, facilitating use with a regular loudspeaker system. Stax used to make these (SRD-7 Pro) and there are also current offerings (from the like of Woo Sound - the Wee). However, I don't see how the serious audiophile would be willing to insert one of these between their amplifier and loudspeaker. One can also of course wire the loudspeaker input to a phono jack so as the normal headphone output can be used. As for me, I'd just stick to the companion amp.
  • Stax and Other Makers Stax is virtually synonymous with the ESL Headphone. There have been others, but they have been few and far in between. In the past, there have been Koss, Beyerdynamics and perhaps others (some are rebranded Stax). Now, paradoxically, there may be renewed interest, as Sonoma and HiFiman have just made their rounds at HiFi shows with their new ESL headphones, which are due for release. Caveat, I think these are likely to be more expensive than Stax. What is more interesting to me is the Shure KSE1500, recently well reviewed by John Atkinson in Stereophile (November 2016), a unique in-ear ESL design with a portable amp, expensive but quite different. Even more interestingly, in the same issue, Herb Reichert wrote of the Koss ESP 950/E90 ESL system (link), still in production but issued in 1990, a full 26 years ago. HR compared them favourably, indeed preferred them to Audeze's magnetic planar LCD-X and LCD-4 (the same article contains links to TJN's 1992 review). Also, another Stereophile reviewer Steve Guttenberg also presents another view in cnet, and the article also interestingly compared the Koss system to the Stax SRS-2107 system. These are all worthwhile reads, highly recommended.   
  • My Stax Experience-Vintage Over the years I have periodically encountered STAX earphones, always to great satisfaction. Just a few years ago, along with his AKG 501 and 701 and Grado RS-1, the same Andrew also lent me his old Stax SR-3 and SR Lambda Pro, with a driver. While I had sampled the AKG's and Grado early on, because of the nuisance of hooking up the dedicated amp, I never listened to the Stax's until I had to return them to him. And boy, what had I missed! For the hallmark sound, see description below.
  • My Stax Experience-Current In NYC my friend Kane owns the current SR-507 with the tubed SRM 007tII amp. As I remember, the sound is luxurious, in the same vein as below.
  • (In)Visibilty of ESL Despite its virtues, ESL technology has always been on the fringe of audio, and this is as true of ESL headphones as ESL loudspeakers. Imagine, a great company like Quad has not had US distribution for a few years until recently. Part of the reason must be the difficulty in servicing Quad ESL's (costly and cumbersome). But Stax headphones are a different story - they are famous for their longevity and many old units are working perfectly. One interesting observation: If you google "electrostatic headphone" you will get Stax among your entries, but if you use "electrostatic earphone" you get pages of Shure only. The vagaries of googling!
SRS-2170 System (SR-207+SRM252S) (Official link with spec's)
SRS-2170 is Stax's entry level system. As it comprises both headphone and matching amp, the package is very reasonably priced in my opinion. It has been well received and even managed to have a few reviews (see cnet and avhub). I agree with those and shall be brief here.
  • Comfort is unsurpassed.
  • Sound Although "entry level", these deliver Stax's hallmark sound that can only be called luxurious, with a large soundstage, plenty of air and warmth. Nothing grating to the ear, yet everything was crystal clear. (the same cannot be said about some of the current, very hifi cans). As expected from ESL, transients are fast (but natural) and bass is tight and tuneful.   I cannot imagine better replay of classical music. Large orchestral music have scale and flow that surpass the usual dynamic headphones. To name just one very important virtue: a very realistic rendition of massed strings (many modern designs fail miserably in this). Chamber music is even more superior - what glorious string tones and tensile interaction! Jazz also benefits from the fast leading edge - pristine percussion and brozen brass, all with superb rhythm and pace. Another difficult feat: a reasonable facsimile of  hall sound, if that can be portrayed by headphones at all. It all adds up to one word: natural.
  • Upgrade? Personally, I don't really think so, or at least not at all in a hurry. Although this is entry-level Stax I don't really hear that much difference between the SRS-2170 system and the more expensive vintage Stax or the current (middle level) SR-507/SRM007tII that my friend has. The SRS-2170 system is an overachiever that has most, if not all, of what Stax has to offer, at an eminently affordable price. I am sure you get more as you go up the ladder, but it is likely a case of diminishing returns.

  • The Best For once, I shall say what is the best: Stax, even entry level, is the best for me, and I am not at all tempted by newer and sexier offerings. If you are into headphones at all, you should try Stax. Stax is durable, and older offerings offer much the same sound and can be obtained at bargain prices. Just get one!
  • vs Planar Magnetics The hottest headphones of today are almost all planars. I have never had one in my own system, but I know the sound. A good analogy is Planar Magnetic loudspeakers (e.g. Magnepan) vs ESL loudspeakers (e.g. Quad and Martin Logan). Now, I know quite a bit about that, as an owner of Maggies and Martin Logan, and interested student of Quad. With large speakers, ESL suffers from dynamic limitations, and in the case of Quad (except the 29xx series) less than full size images, while Maggies tend to grate a little in the treble, not as refined and luxurious as the ESL's. However, with the cans over our head, the situation is totally different. Unless one listens to heavy metal and a steady diet of rock (which is not the average audiophile), I personally have not heard better than Stax, and shall remain an ardent fan.


  1. Any experience with the HK brand, KIngSound and their electrostatic headphones? Also, do any of your audiophile friends use Gryphon products from Denmark? They make a wide range of products from digital to speakers but do you have any feelings about their amplifiers in particular?

    1. I actually know some King Sound people, but have heard only one of their early ESL loudspeakers. Quite good. I have there may have been QC issues, but I really am not sure.

      Gryphon? If you ask me, not worth anything. I'd take an old PASS class-A over any of their stuff. Warm but without detail and rhythm. Just plain boring. One of my LEAST favorite brands. Sorry if that rattles you.

  2. Rattled? Hardly, as I just wanted to get your opinion on a legacy hi-end brand ala Krell, Cello, Jeff Rowland, etc. I don't own any Gryphon gears and haven't had a chance to audition them in several years as they have disappeared from the North American market due to lack of distributorship. I did have an extended opportunity to hear Gryphon's Tabu amplifier back in the late 90s and I thought it was quite smooth sounding & on the warm side of neutrality. Of course, it was disappointing to learn that one could purchase an NAD S300 and essentially get the same sound as it was just a re-badged Tabu.

    I have heard the King Sound electrostatic headphones and found them ok. I only heard them with their matching solid state amp though and didn't get a chance to hear the tubed version. They also had a matching CD player on display but it appeared to be a re-badged Audiospace CD player in every aspect.

    1. I am basically a tube man, who is not usually impressed by solid state that tries to emulate tubes (Class A usually). Gryphon is one that fails. Pass is better. There are some gems (relatively speaking): one is the original Musical Fidelity A1, designed by none other than Tim Paravicini; another is old Accuphase integrated amps, great phono section and sound and they run hot (much superior to their current offerings).

      That said, solid state amps come in handy sometimes. I use them for my Magnepans. In HK I use a very old Bryston 4B, in NYC an old Sunfire (very good).

      I always use a tube preamp.