In this feature, we review the EarMen ST-Amp, which is a balanced desktop integrated DAC and a 1.85W capable headphone amplifier. It is priced at $599.
Disclaimer: This sample was sent to us in exchange for our honest opinion. Headfonics is an independent website with no affiliate links or status. We thank EarMen for their support.
You can click here to learn more about EarMen products previously covered on Headfonics.
Note that this article follows our latest scoring guidelines, which you can read in more detail here.
It is arguable that the new EarMen ST-Amp is not the usual DAC with an amplifier combo but rather an amplifier tailored with a DAC.
As I understand from the write-ups of EarMen for the ST-Amp they wanted to deliver an amplifier that can fully reflect the DAC installed or any downstream signal coming from an external DAC.
Let’s remember as well that so far, this is the first desktop-class design by the company that serves those shopping for an all-in-one. The closest cousin to the ST-Amp is the more expensive Angel which is in the portable segment.
So as a pioneer in this new market segment for EarMen, I believe there is a huge expectation here for the ST-Amp.
Tech Highlights
The EarMen ST-Amp uses a single ES9280 DAC chipset capable of up to PCM 32BIT/384 kHz and DSD128 over DoP.
Checking with its peers, only the Eagle had a similar DAC configuration which is an ES9280 C Pro. The higher-end standalone desktop DAC of EarMen, the Tradutto, uses the more popular ES9038Q2M chip.
The ST-Amp shows off its fully balanced circuitry with no less than three 4.4mm jacks around with the third fitting turning it into a proper standalone amplifier.
In a balanced configuration, with the inputs and outputs all set properly, headphones get to squeeze the ST-Amp every ounce of its 1.85W maximum power. This should be enough for most gears out there and shouldn’t be scoffed at unlike the more anemic 0.5W output of the amp when plugged in using single-ended connections.
What I didn’t notice immediately when I was using the ST-Amp is that it has no gain setting. While it’s nice to have some flexibility in this regard, it’s not a deal breaker in my book unless you require some serious horsepower.
Design
If you’ve had the pleasure to check out the other desktop offerings of EarMen, the ST-Amp uses the same footprint as the CH-Amp and Staccato. The unit weighs 1.1kg and is also being held up by the same tall feet EarMen used previously.
Since adding the ST-Amp on top of the pile stacks very well, this makes me wonder if this is a preview of what’s to come. Still, it is a different matter when we begin to compare the facade with a clear distinction that the design inspiration of the ST-Amp came from elsewhere.
The blockish chassis has a completely different vibe bringing in cues from both classic and modern styles. With crisp lines and a clutter-free layout, the ST-Amp looks fresh and won’t find it too difficult to blend in any living room or listening area.
Without necessitating a screen, in place in the middle is a huge analog volume wheel with raised markings around to act as a guide. The black color adds strength to the visual impression of the sprightly painted front.
The ALPS potentiometer used feels high quality. It rotates heavily but glides smoothly with effective control of the volume at every turn.
On the left are short and snappish analog switches. I like that they are out of the way but with odd-numbered feet supporting the ST-Amp, the rear corners sometimes wobble when I hold the unit wrong while switching the unit on.
I/O
The ST-Amp we have here is keeping things short, sweet, and with its eyes on the price. The usual optical and coaxial inputs are missing and Bluetooth is also axed out.
Instead, we have to remember that EarMen placed more emphasis on the ST-Amp as an amplifier so a single USB-B input is what they decided is the minimum users would likely need.
With a balanced circuitry inside, of course, EarMen is opening its potential by allowing users to tap into the ST-Amp using appropriate connections. What can be discovered here is three space-saving gold-plated 4.4mm jacks for headphones, pre-out, and analog in.
Sure, for single-ended users out there, the 6.35mm output in the front and the RCA jacks at the rear is keeping the compatibility easy. Just note that the dynamic range of the ST-Amp in this setup drops down to 117.9dB single-ended as opposed to 126dB from its balanced output.
Controls
For your safety, the first order of business is to set the proper input voltage of the unit at the back. After that and connecting the ST-Amp to either a digital or analog source, there’s now very little to think about when operating the device.
With two snappy switches in front, tip the leftmost one up and the ST-Amp will boot up. It is pretty quiet when it starts, so look for the light indicator just underneath the switch and wait for it to glow white.
To keep using the internal DAC, leave the only toggle left pointed upwards. Putting it in the downward position not only initiates amp mode but also turns off the digital section which I established when the ST-Amp disappeared from the list of DACs in my computer.
With two jacks upfront, I tried using both at the same time but it seems the ST-Amp only allows the single-ended output to run in this setup. I expected the 4.4mm output to at least be the one left on since it has the higher power but EarMen went the other way around.
Lastly, unlike the CH-Amp which has a relay to turn off the pre-out when listening to headphones, the ST-Amp keeps an active signal coming out the rear at all times. There is no line mode so it simply follows the set volume in front.
Packaging & Accessories
Both the CH-Amp and Staccato review units came from the USA so the ST-Amp is the first EarMen product I received directly from Serbia. Either way, it is nice to note that EarMen is keeping things uniform by also sending it in a white single-walled cardboard box that protects the more appealing packaging inside.
Unlike the ordinary outer shipping container, the more official box is finished in a minimally textured black wrapping with an EarMen logo square in the middle of the top cover. And taking a glance at the bottom, all the important specs and features of the ST-Amp have been listed as well.
Now if you’re too excited to admire the packaging and skipped straight to the contents, then I have a bit of news. Aside from the actual unit, user manual, a bag of silica gel, and a pile of protective foam, EarMen sadly left out sending a power cord and USB data cable.
It’s a good thing I don’t have a shortage of extra cables at home. Otherwise, I’d still have to do a quick shopping to get the unit up and running.
Sound Impressions
DAC/AMP
Let me first cover the basics and tell you why the ST-Amp shouldn’t be treated as any less of a DAC/Amp combo before I use it as a standalone amp in the next section.
EarMen made a great decision in letting the ST-Amp be its own thing. Unlike other EarMen products I’ve tried, the ST-Amp seems to be the cheekiest.
Both cool and playful, there’s an easiness to low and trailing notes that gently treads neutrality but isn’t afraid to shift to a bolder sensation when a bigger scene asks for it. It also operates with a surprisingly copious amount of punch that supports the clear but slightly rounded delivery.
It buckled a bit when I realized that familiar recordings where singers take a deep breath have been ironically shaved of airiness. Instead of unfolding the layers to support the main draw of the breath, the part seems more urgent or forced.
The ST-Amp does not resist a sharp singer and chime to show its energy. Substantiating it with body and fluidity, the result is a pristine edge without sounding anemic.
Electric guitars have the right amount of presence and don’t seem harsh or out of place when it starts to get into the shriller parts. It does lack a bit though in delineation but continues to attack well without sounding thin.
One of the things that make me listen to the ST-Amp is that I like how fine the instruments are scaled and positioned. While it does get surprisingly far away staged instruments still have an excellent acoustical arrangement.
What it lacks is that last bit of expression missing to create a completely involving picture. A minor complaint, but I think if only the extension could have been more expansive, the ST-Amp will be a solid all-in-one.
Amp
I’m surprised with the apparent jump in clarity and resolution the ST-Amp showed when I flipped the toggle switch to use an analog input. If the ST-Amp isn’t impressive enough already as a modest combo, then using it as a standalone amp will be opening endless possibilities plugged into higher-end DACs.
Opening up the sound a bit more, the low-end of the ST-Amp is not anymore as forward. The punch and mid-bass presence is still sufficient but is now less playful and intimate.
With a more sober appeal and improved detail retrieval, it is great to see that plucked strings are now easier to pick apart down to their reverb.
The ST-Amp has softened up the edges of a whispery note without letting the detail and layering suffer. This essentially improves the timbre and dispersion of vocals to be more natural and even.
I think the DAC has a lower midrange bump that the standalone amplifier lacks since guitars are a bit sweeter when the ST-Amp is set to use the USB input. But in both cases, the twang of the string is steely and vibrant.
Click on page 2 below for pairings and our selected comparisons.
