STAX SR-003MKII HEADPHONES & SRM-D10 DAC/AMP/ENERGIZER REVIEW

Stax doesn’t really need any introductions, and this $2250 combo is being released to celebrate their 85^th Anniversary. 

Stax are now part of Edifier Global and have been one of the pioneers in the electrostatic audio world. Known for making excellent electrostatic headphones, energizers/amps, and earphones; this portable combo allows you to experience that signature Stax sound “on the go” (more on this later). 

FEATURES AND BUILD

The SRM-D10 is a portable electrostatic energizer, amplifier, and DAC outputting pro-bias (580v) out of a transportable device. It has an internal DAC (fully DSD compatible up to DSD128) that is fed from micro-USB (USB-C would be much nicer) along with an analogue 3.5mm jack input, standard 5-pin output, and an internal battery. The internal battery life is rated at around 3.5hrs when using the internal DAC or 4.5hrs using the analogue input, but this will vary slightly depending on the volume and headphones used. The battery charges from an AC plug, not USB. 

The SR-003 MK2 use a new driver that is lighter in weight giving them an improved transient response, finer resolution, and increased transparency; they also have new eartips with 3 sizes included in the box. They are designed to be listened to open-back and have a headband should you wish to have a more secure fit. They come with covers to convert them into closed-back earphones too, these are not really designed for portable use though and are better for stationary listening, thus being open-backed isn’t usually an issue. They come with a standard Stax 5-pin cable and run-off pro bias outputs. 

Build quality of the SRM-D10 is superb, aside from the micro-USB it is a solidly built portable DAC/amp/energizer. The volume control/on-off switch is smooth and a pleasure to use, there is some heft to the unit and it feels like it is built to last. 

The SR-003 MK2 headphones also feel well-built. They are mainly plastic to keep the weight down but they are well put together and anyone buying these would, in my opinion, know how to look after them. There is a grill between the eartip and nozzle but the openings are quite large, so keeping them clean would be advisable to keep them running well. The flat cable is thin, but I do not see any issues with it if these are looked after properly, there is good strain relief where needed.

COMFORT OF THE STAX SR-003 MK2

The SR-003 MK2 are unusually shaped, which is to accommodate their larger electrostatic driver, however when used with the right tips they fit just right without falling out. The housings are lightweight which helps a lot, but these are not designed for active use. I found them very comfortable without the headband, but I found the headband caused some discomfort after a while so I opted to remove the earphones from it. It is great to have the option though and I can imagine some will prefer the more secure fitment of the headband.

To me, it is clear these are more designed for at-home use due to the fact they sound best open-back, and the SRM-D10 has limited battery life. This would also suit those who travel and want an excellent-sounding travel setup to use when staying in hotels, for example, or someone who wants to take their setup out into the garden for a couple of hours. Whilst it is technically “portable” I would classify this as transportable and something that can be transported between locations rather than for use on the go. 

SOUND QUALITY

I’ve been using this combo for a bit now and have been getting to know it well. I’ve mostly used it via the USB input playing from Roon on my PC. Electrostatic systems are something I’ve experienced on quite a few occasions and I appreciate some of their traits, whilst others don’t appeal to me so much. 

Here we have an earphone setup that can be moved between rooms and listened to without the weight of over-ears. It is a system that has a very complete and open sound that does not sound like you are listening to a set of in-ears. These compete with good headphones in my opinion, and the SRM-D10 has plenty of power to drive these to unlistenable levels. 

Like many electrostats, these are quite genre-dependent and they will, in my opinion, sound best with certain genres and not-so-great with others. These are not a natural all-rounder, but they do have a well-balanced sound that comes across with natural tonality and a hint of warmth. I think it’s something to do with the dynamics, but most electrostats don’t seem to do very well with anything heavy, or that requires a good amount of impact and punch. 

Where these really excel is when you play something acoustic, Lights’ – Almost Had Me from the Skin & Earth (Acoustic) album is jaw-droppingly good through this little setup. Every finger sliding across the strings is easily audible, the reverberation from the guitar is as full and warm as it should be, and her vocals sound pitch-perfect. This kind of music is where you really hear the voicing behind these headphones and I think they were made for acoustic, jazz – softer music that you can sit back and get lost in the beauty of it. 

There is a lovely sense of space and air around each instrument, creating a realistic soundstage that is enveloping without sounding diffuse – echo effects trail off smoothly and there is no lack of extension in the low or high end. There is a high level of resolution and low-level detail is presented very well and you can easily distinguish each part of the recording. 

A little secret, I’m a sucker for certain musicals, and The Phantom Of The Opera is one of my favourites. I have the soundtrack from the film (I know it’s not to everyone’s taste) but the duet during Past The Point Of No Return sounds excellent through the SR-003 MK2. It seems the midrange is a strong point, but it is backed up with a full low end when called for – their ability to handle switches from large orchestral pieces to soft vocals is most impressive.

One of my favourite test tracks is Deolinda – Passou Por Mim e Sorriu (ao vivo no Coliseu dos Recreios) and this little system passes with flying colours. You can hear the acoustics of the hall, the double bass is deep and controlled, and everything comes across as unforced and is presented in a very natural way. 

As I stated earlier, these seem to favour those softer genres and moving on to something like Saosin – Some Sense of Security they do an admirable job, but they do sound a bit flat with this kind of rock music. It’s interesting as there is plenty of body and dynamics for orchestral music, but rock seems to just lack urgency and punch, the midrange is still rendered nicely though.

City and Colour – Commentators on the other hand sounded great again with a nice open sound with effortless treble extension and a nice warmth to the sound. There’s a good balanced between being revealing and being enjoyable – they’re not overly clinical which means it’s easy to just sit back and enjoy the music with these.

The SR-003 MK2 render textures in acoustic and softer folk music perfectly, making them a match made in heaven for these genres. To me this is the reason why enthusiasts have different earphones/headphones, as each has their area of expertise, whilst some do make good all-rounders. The SR-003 MK2 with the SRM-D10 would fit very nicely into a collection for those times you want a snappy and tonally true performance from real instruments. I absolutely love the way these render both male and female vocals and their ability to sound very open and spacious, something most earphones struggle to do. 

CONCLUSION

Whilst these may not be the most ergonomic earphones, and they have design limitations that mean their use case is also quite limited, they do offer up stunningly good sound with the right genres. Keep it smooth and you will be greeted by a natural and spacious sound with excellent detail retrieval and snappy transient response. Overwhelm them with heavier genres or anything overly bass-heavy and they do sound a bit thin/lacking dynamics and punch. 

These are for kicking back and relaxing with, they are not tuned to get you dancing around the room, or get you headbanging, but they do what they are tuned to do exceptionally well.

The SRM-D10 powers the SR-003 MKII with ease and is a lovely little transportable DAC/Amp for Pro-Bias electrostatic earphones and headphones and I think this is well worth looking into if you don’t want something you can’t move to another room. 

AT A GLANCE

Build Quality:

The SRM-D10 feels very solid, but USB-C would be better than Micro-USB 

The SR-003 MKII are plastic but well built, the construction keeps their overall weight down which is good for the comfort side of things.

Sound Quality:

These have a very natural and open sound with softer genres, they do however lack a little urgency and dynamics with heavier music

Value For Money:

The level of sound quality you get from this small setup for the price is very impressive, one that is usually reserved for high-end over-ears. 

We Loved:

The midrange is simply stunning, they are easy to fall in love with sonically. 

We Didn’t Love So Much:

Not the most versatile earphones, lending themselves to certain genres and not others. 

Elevator Pitch Review: If you are looking for an earphone that will sound breathtakingly good with softer genres, then the SR-003 MKII + SRM-D10 combo is well worth looking at. Designed with “portability” in mind, you can take this setup travelling, or around the house, and get that tonally realistic and responsive electrostatic sound Stax is well known for. 

Price:  $2250

Oscar Stewart