Auris Audio: https://www.aurisaudioshop.com/product/euterpe/
Tour arranged by @msheney and Auris Audio. My time with the Euterpe was too short, but luckily a weekend built in gave me an extra day. So, still too short, but enough to garner good impressions. I thank both for the opportunity to audition this Serbian tube amp, it fits in quite well into a packed mid-fi laden market. Some fairly unique characteristics along with tried and true features make the Euterpe worthy of a listen.
For a much more detailed look into the history of tubes and the functioning’s of the Euterpe, I suggest @wiljen excellent prose. He is quite knowledgeable with tube technology and gives an excellent historical of the technology (as it relates to the Euterpe with more coming, he tells me…).
Wiljen’s Euterpe review: https://audiofool.reviews/2019/09/11/auris-euterpe/
I was approached by msheney regarding the possibility of a review for the Auris Audio Euterpe along with @wiljen, and @army-firedawg. Betwixt the three of us, we went through two Euterpe’s. A certain shipping company mangled the sample sent to Will, so I was the lucky recipient of a brand-new Euterpe. Except another shipping company delivered said product (they told me so…) to my address. Well, unless my dog hid it in her doghouse to wow the local wildlife, it was not there. Thankfully, my neighbor (who had been gone a month) upon his return looked on his front porch to find a plastic wrapped package, yes, the Euterpe. I spent 15 minutes undoing the Auris pack-job finding an excellently wrapped product. I truly believe it could have been dropped over Niagara Falls with no damage.
So, three days after said shipping company (which I now despise) said it was “delivered,” I listened. Will had graciously sent me extra tubes in which I will discuss, to compare between the stock. I understand why a company ships with the stock tubes, but sometimes they are not the highest, but out of necessity, industrial for longevities’ sake. This would be a case. But the stock tubes do sound quite acceptable. And to me, having easily accessible tubes in such a critter is half the fun. Much like changing OpAmps in the Burson set-ups (which will be compared), fine-tuning can be quite satisfying. All was good, and I was afforded a full-on dedicated listen the next day.
Initial impressions were one of competent sound, good power and decent enough extension up top. I will leave the finer points of the DAC vs amp sections to your reading of Will’s review. He does a nice job of stating that the DAC is slightly cooler (and brighter), which counters the natural proclivity of tube sounds to be warm and rich. I would agree and found the stock tubes to be on what I will call the lighter side of listening from other tubes of which mine ears have graced. Not unpleasant, but different. I would call it refreshing. If I was doing a blind test, I would almost call it a solid-state amp. Many of you would be able to pick out the difference, but to me that is what Auris has brought to the table with the Euterpe. Perusing their website also gave appraisal to their higher priced tube amps. The Euterpe seems to be positioned as the “entry-level” headphone amp, and as such might be the first foray into Auris-world for some. I am intrigued by many of their offerings based upon the website and would welcome comments surrounding others you may have tried.
Tube: 1 x ECC81 , 2 x PL95
Amplifier Configuration: Single Ended
Power output: 0.9W
Conversion rate: USB: DSD64, DSD128, PCM max 32bit/384kHz
Output Impedance: Low 32-80 Ohm / High > 150 Ohm
Power supply: 115 / 230 VAC
Inputs: 1 x USB, 1 x RCA
Outputs: 6.3mm Stereo / RCA Pre Out
Dimensions (WxLxH) mm: 270 x 210 x 230
Weight (kg): 4.1/NET (without PSU)
Weight (kg) PSU: 1.1/NET
Dimensions PSU (WxLxH) mm: 95 x 185 x 55
iFi Pro iDSD
XDuoo X10T ii
CTM Da Vinci X
Mr. Speakers Ether-C Flow 1.1
Campfire Audio Cascade
Sendy Audio Aiva
Coldplay-All I Can think About Is You
Dona Onete-Sonos de Adolescente
Los Lonely Boys- Heaven (en Espanol)
twenty one pilots-Trees
twenty one pilots-Car Radio
twenty one pilots-Heathens
Damian Marley-Everybody Wants To Be Somebody
Damian Marley-So A Child May Follow
Damian Marley-The Struggle Discontinues
Ziggy Marely-See Dem Fake Leaders
Mark Knopfler-Laughs And Jokes And Drinks And Smokes
Santana w/ Mana- Corazon Espinado
The new twenty one pilots album, Trench
Tedeschi Trucks Band
Big Head Todd & The Monsters-Beautiful World
This sample came completely packed and sealed in palette wrap as well. The box even had side protectors on every side, then palette wrapped. A nice touch, but a pain to undo. I would rather have it that way. Finally getting into the box, you are presented with…another box. Opening that and you find soft foam pieces laid on top. Take off the top piece and there is another, which has a cutout to house the well wrapped power unit. With the soft quality of cheese cloth, the power unit is well protected. Plus, you get your first look at the fabric wrapped power cord, which attaches to the back of the Euterpe. From there, you lift out the foam to find another flat piece, which has a cutout near the bottom to accommodate the metal base. Well thought out. Lifting that piece off reveals, you guessed it a well wrapped Euterpe. A 3” soft foam piece sits beneath the Euterpe to protect it from the bottom. Very well packed, and others should take lessons from the quality wrap.
Borrowing the design from Kennerton, Auris presents a smaller footprint, which would be at home on a shelf in your office, or above your workstation or on a side table. Doubling as a headphone stand adds a bit of quality as well. With three slots in each side, you cannot help but notice the tubes glow. Another nice feature. The amp itself has a smaller footprint, dominated on the front by the volume knob, which doubles to turn the Euterpe on as well. An analog/digital toggle resides lower left, while a low/high impedance toggle resides lower right. A 6.3mm jack resides equidistant below the toggles. I will note that switching from low to high impedance yields a bit of sound change, and Auris recommends the change at 150 ohms (above/below). I will note that as of later in me week, the impedance toggle drew static to the sound when touched. I could also get one side to cut out occasionally when I switched between. I will also note that between Will’s and this one, the switch for EL95/PL95 goes from a toggle (on his) to a dedicated switch on this sample. So, adapting changes seem to be on the fly. This can be good or bad.
Quality is good for the build, save the toggle I mentioned. On the back you have a female USB connector for input along with RCA in/out connections. That’s it. While you can certainly use the USB connection to vary what you input (iFi make a nice cable, which can be used for various devices), you have either that or the RCA. No balanced out or in limits what you can do. But I am beginning to find that when one hits this level, you are going for pure sound capability. Much like the Dethonray DTR1, which I borrowed from Will (I just ordered on myself and it is good…REALLY good), you end up not missing the balanced output.
Powerful to a point, you can reach 0.9 watts, which for a desktop headphone amp is nothing to sneeze at but might not be enough for harder to drive planars. I found no problem running my Ether-C Flow or others. Coupled with a powerful DAP, you can drive music to very high levels.
Using the stock tubes initially, I let the Euterpe play for close to 20 hours. I found no difference in sound, but others may. The sound was one of what I will call “cautious.” Emphasizing the top end to even out the warm nature of the tube sound, the treble seemed light a bit airy and lifted. Almost like I was listening to a DAP on the brighter side of life. The sound was quite nice, but it felt a bit shallow and hollow to me. It lacked depth. But, as stated above when one has a tube amp, one does not leave alone (unless you are satisfied, and some will indeed like the stock sound). One changes tubes until you get the sound you prefer. A true benefit of the tube sound, and credit to Auris for making the tubes visible, giving a wonderful look inside the wood; but also, easily accessible for changing. Just make sure both the Euterpe AND the power source are off. Wait until cool, then change to your hearts content.
Bass was good, with a warmth of sound I appreciated. Mids were not too revealing, with female vocals sounding quite welcoming, but not overly aggressive or forward. To me, the mids played back behind the scenes, and the female vocals highlighted this aspect. Male vocals on the other hand showed well, with a bit more depth. Not much mind you, but the set up seemed to react better to the male vocal genre.
Layering and separation was quite decent as one would hope at this price. On more complicated songs, I lost detail and the ability to clearly delineate layers, but on. A succinct distinct song such as Carry On Wayward Son, from Kansas there was a staccato of distinctness, which allowed the band to show. One of my all-time favorites, anyway, turning the volume up made me nostalgic. Good stuff. Each instrument in Kerry Livgren’s wonderful arrangement was where it should be, right and proper. His arrangements are simply. Superb, and here the Euterpe showed well. All of the above was heightened when using Will’s tubes. Man, it made me think I was almost watching Kansas again live. Superb showmen, and an incredible show. Memories…
Switching to the tube loaned from Will, I switched to the Mullard PL95 for power and the Cardsafterhours 6201 for the pre-amp section. A nice US-spec’d pre-amp tube made all of the difference. Moving the sound to more depth, with a rich tone that I liked, that hollowness was gone. Full and deeper bass ruled the tone, with less push up top. Mind you the treble was still quite good, and can be source dependent, others have noted that you. Should start by changing the pre-amp tube first. The stock power amp tubes are quite acceptable and good. Most should be satisfied with the sound, and to check I played the US 6201 with the stock power amp tubes. I liked the sound, but the Mullard’s are a definite step up. In conversation with Will and @expatinjapan, we noted that you could certainly spend more on tubes than the amp cost. If one goes that route, I would suggest you look at the higher offerings from Auris or others.
I would suggest you spend a good week or so with the stock tubes, to let them set in; which will allow you to get comfortable with that baseline sound. Then change the pre-amp tube first. I found that using the stock power and US 6201 pre gave good sound on rock, such as The Pretenders or The Kinks. The music just rocked, and you do not need that extra “cleanliness” of sound. But if you are listening to music, which needs a more discerning sound then you would be wise to change all three.
Comparisons and sources (with aftermarket tubes):
Staring with the CTM Da Vinci X, I found the treble to be better contained. I will admit I do love the sound, but after a good listen the X can be a bit bright for me. Easy to drive, I never took the Euterpe past 1000, for it became too loud. The airy crisp sound of the Da Vinci was tamed a bit giving an almost refreshingly new sound, which was a bit darker using the non-stock tubes. I liked it and the combo reminded me of my Mentor V3 in almost any situation.
Switching to the Mr. Speakers Ether-C Flow, I relished the sound as an excellent way to drive my favorite closed-backs. With bass more akin to what I expect in a closed back (think Cascade…), the Ether sounded warm, rich and less analytical. The sound is one in which I judge most headphones that come my way and the Euterpe made it more so. Shrinking the top end treble only made for a more satisfying sound to me, but without feeling like the sky was falling. I enjoyed the sound immensely. That said…
By far my favorite headphone of the week was the Campfire Audio Cascade. The pair seemed meant for each other, bringing that bass under a bit of control, which could be missing in some sources. Matching warmth with warmth, this was not too much. Sometimes you can add warmth (or cold analytical) to something of the same and it just doesn’t work. It is too much and it doesn’t sound good. Here though, the combination was superb. It would be a wonderful work set up, where you could turn the music up without care due to the closed headphones; and I would admit that your productivity would rise to the occasion!
I did start with my MBP & Tidal for the opening few days. While Tidal Premium is an enhanced sound, I do like it for the bass and crisp nature (for me). As such, I can tell when something adds or subtracts to the sound. With the Euterpe, the sound was a bit bassier and a bit clearer. I enjoyed the enhanced sound. That said it wasn’t until I hooked the Euterpe to the DTR1, that it really began to shine as well as the X10T ii. Both are based solely upon sound quality as the most important aspect.
The DTR1 is pure sound. Coming with only a 3.5mm jack, the cost goes all in on the sound. With a very basic operating system (I would say a bit archaic and needing an upgrade), the sound is marvelous. Adding to the Euterpe, a warmth emanated that is absent when using other solid-state amps (except the Pro iDSD, which is a hybrid). I found that the bass became richer, and a bit deeper. Treble, which was good to start with became a bit more rounded. Not a bad thing. Sound stage was also a bit wider. Alone, the DTR1 is one of the best units I have heard. If you want unadulterated pure sound, and can live without frills, then look at the Dethonray. Combined with the Euterpe, this quickly made me think of. My XDuoo x10t ii/iFi Pro iDSD combo. I thoroughly enjoy that sound and the DTR1/Euterpe enters at the same level.
Listening the x10t ii/Euterpe currently, I find the qualities, which drew me to the XDuoo to be a bit more. Another (actually a transport only), which brings pure sound to the table, the Euterpe adds a bit of bass and a richer sound. Similar to pushing the XBass button on my iFi xDSD, the Euterpe tubes add that sound without having to push a button. This too, would be an excellent desktop/office set up. Simply plug the combo in, hit play and listen using your favorite headphones. Lost in the sound, you could not be happier to get away from the mundane sounds of the office.
Compared to my iFi Pro iDSD, the Euterpe is simply spartan, utilitarian or void of options with which to tune the sound, save low/high impedance. The real fun is changing the tubes in the Euterpe. The iFi has switches and gizmos to do that. And if one wants to be able to change sound quickly, the iFi has few peers. Costing half-again what the Euterpe is, I find the sound comparable, but with many more options, the difference comes to the front. I can get that same tube sound and alter the sound signature of the music as well. With the Euterpe you are bound to the source. Not a bad thing, and really not meant for that many options. If I had heard both side by side before purchase, I would still have come home with the iFi. But based upon options, not a huge difference in sound.
Throwing the Burson pair into the mix may seem odd, except when one considers that Burson built their reputation on OpAmp changing (in less than five minutes mind you) the comparison is valid. Running the V6 Vivid Opamps, the sound mimics a warmth which I prefer. In that regard, the Burson hold up well. When paired together, you get a very competent pre-amp, and a wonderful, powerful amp. And when you consider the cost of both, in stock form can be had for $600, you have a real treat. Even throwing your preferred Opamps only adds another $200-300. So, the Burson pair can go toe-to-toe with items such as this. Even with the V6 Vivids, the sound is still bright. That warmth of the OpAmps cannot overcome what is a bright sound to start with. But it is clean, clear, crisp and wonderful. Something to consider if one wants an affordable pair, which can be tailored to your preferences.
Finishing my time with Boom Boom playing from BHT&TM, with John Lee Hooker, I get why I like the sound. There is a certain “dirtiness” to the song. A kick the seat back and find an open road to it, John Lee’s vocals simply give it that down home sound. The Euterpe adds to that dirtiness. Giving more. Adding a breadth of sound, which through tubes makes the sound oh so sweet. Follow that with Please Don’t Tell Her, and you understand from where Auris comes. One need only look at their website to garner a look at the more expensive wares. That technology used trickles down to the Euterpe well. And if this is their entry sound, one can only wonder what the more expensive units sound like. I am thoroughly satisfied with the Euterpe sound, and would consider it if there were more options to inputs and maybe adding a balanced-out option. But as stated earlier, as a stand-alone pure headphone amp, the Euterpe can muscle into the $1500USD quite well.
I thank msheney and Auris for the loan of the Euterpe. It is quite good and well worth a listen, even if you are interested in more listening options.