Euterpe reviews at Head-Fi.org

Auris Audio Euterpe ($1599): A woody with tubes.

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.


Specs (Euro):

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


Gear used/compared:

iFi Pro iDSD
Burson Play/Fun

Dethonray DTR1
XDuoo X10T ii
MBP

CTM Da Vinci X
Mr. Speakers Ether-C Flow 1.1
Campfire Audio Cascade
Sendy Audio Aiva






Songs used:

Coldplay-All I Can think About Is You
Coldplay-A Message
Coldplay-White Shadows
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 Marley-Lighthouse
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


Unboxing:

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.



Fit-n-finish:

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.



Sound:

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.



Conclusion:


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.

Packaging / Kit:

I received the tour model Euterpe which came in generic packaging so cant speak to the retail package. The tour model ships with the unit, a set of EI tubes, and the power block. It did not ship with a power cord, but a standard C14 receptacle is used on the power supply so a standard C13 or C15 power cord is all that is needed to round out the package. In a pinch, a standard computer power cord will fit although I do recommend using something a bit better shielded.



Build:

The Euterpe is both beautiful and functional. The wooden outer panels are straight grained but well stained to show the figured they do have. The windows through the panels put the tubes on full display, and the internals tuck neatly into the middle where they disappear into the background and just let you enjoy. The function as a headphone stand makes the Euterpe strangely utilitarian for such a high end piece of hardware. Controls are well done with switches being very positive and the volume knob having good weight as it doesn't take effort to turn but doesn't feel like it is going to fly out from under one's fingers either. Front controls include the source switch for pre-amp input from an external DAC or direct USB input using the internal DAC, an impedance switch (below 150Ω vs above), and the volume knob which doubles as the power on/off. The reverse has two sets of RCAs at top (One in, one out) a USB A female port, and a proprietary power connector. At the top behind the three tube sockets, another switch handles voltage supplied to the tube heaters. In the EL95 position 6.3 Volts is supplied. In the PL95 position that voltage is reduced to 4.5 Volts. The power brick itself is exactly that. It is literally the size and weight of (at least) a brick and does a good job of providing clean power to the Euterpe. My tools to test it are limited but putting it on a scope showed very clean power. The cable from the brick is nearly 5 feet in length allowing for good separation of the power supply from the unit to avoid interference. The cord is cloth wrapped with a proper strain relief as it exits the unit and should give years of trouble free service. The power brick does get warm but is heatsinked both internally and by the case and even after 24 hours of continuous use it is only warm to the touch. Also worth noting, the lack of a provided power cord allows users to adapt the Euterpe to their local voltage (easily switched between 110 and 240) and connector types.









    


Internals:

The Euterpe is composed of a xmos chip that handles USB input duties, a Sabre ES9018 chip handles the conversion duties, a 12AT7 tube handles pre-amp functions with a Mundorf capacitor in line between the pre-amp and power tubes. A customized alps potentiometer handles volume adjustment, and either PL95 or EL95 tubes handle the power duties. The Euterpe is a output transformer designed amp, but additional details about the make and model of transformer used have not been published by the Auris that I can find. The DAC chip is capable of higher resolutions than the xmos input allows so the limits are effectively set by the USB implementation. DSD64 and 128 are supported and PCM maxes out at 32/384. Measured output is 0.9Watts.

The tubes make a major contribution to the sound of the Euterpe, and allow the owner to customize the sound to their liking and their headphones. The pre-amp is the ECC81 or in western vernacular, the 12AT7. This is a very common tube used in a ton of guitar amps as well as audiophile applications. The 12A_7 family of tubes allows the user to substitute other members of the family to boost or lower the overall gain. Auris mentions use of the ECC82 (12aU7) with sensitive headphones. Mμ of the au7 is 17 vs the at7's mμ of 70 so swapping in a 12au7 will certainly lower the noise floor and the overall output power and there are alot of really good 12au7s out there at reasonable prices. Conversely, if you really wanted to increase output power swapping in a 12aX7 with a mμ of 100 will certainly do so. Noise floor is raised considerably by doing so and is probably only useful when attempting to power something like the He6se.

The stock tubes are the EI Yugoslavian made current production PL95 power tubes and a Electro-Harmonix Russian made 12AT7 pre-amp tube. These have respectable performance but limit the overall dynamics of the Euterpe and some notes I have seen to date seem to be more of a critique of the limits of the tubes than of the device. For my testing I first listened to the stock tubes, then went digging through my stash and found a couple GE 5-star 6201s, a Brimar CV4024, and a Telefunken Diamond 6211 to try in the pre-amp spot. For power tubes, I had Siemans, Mullard, and RCA PL95s along with a few Mullard and Valvo EL95s on hand. I came away with the feeling that the power tubes influenced how cleanly the details were presented but the largest changes came when swapping pre-amp tubes. I could live with the stock PL95s if the pre-amp tube is swapped for any of those listed as it dramatically improved the dynamics and brought better midrange performance. The best value among the bunch is likely the GE 6201 which can be found in the $20-$50 range depending on what age and type. The one I used was an early tube with black plates and triple Mica and is one of the harder versions to find, but well worth the hunt in my estimation. Ok, I'll save you the hunt, last I looked Brent Jessee had the 6201 here and the one you want is this one ( 12AT7WA 6201 / GL6201 GE blackplate 5-STAR, Military Grade and 5-star). PL and EL 95 tubes are a bit harder to turn up a reliable source so, some scrounging may be needed but ,if you can find the Mullard (early british made) PL95s, I think they provide the best dynamics of the bunch.

One quick reminder, if switching power tubes, make certain the top switch is in the proper position before powering on the amp. The only difference in PL and EL 95 tubes is the heater voltage/current required so feeding a PL tube the voltage intended for an EL will likely dramatically shorten the life of the tube if not turn it into a flashbulb immediately.


       


Sound:

I have to divide this into three component discussions when speaking of the sound of the Euterpe. Part one is the internal DAC performance vs using an external DAC to feed the unit. Part two is using the stock tubes in the Amp, and part three is tube rolling the amp which changes it pretty dramatically. For purposes of reviewing the Euterpe, I used the HD800, He560, and Empire Ears ESR (borrowed - thanks Jeff).

The internal dac leans slightly to the bright side which makes it sound clean and slightly cool because it really doesn't introduce any warmth to the recording. I don't want to give the impression that the Euterpe is overly bright as it isn't but the DAC contribution is slightly bright and cool and does a good job of balancing the warmth usually added by the Amp stage. I think a warm on warm design might be too much of a good thing and so appreciate the tuning for a more middle ground result. Detail is quite good, but not in the league with something like the Burson Swing and details and transients are improved by moving to an external DAC. The Swing offers a similar tonality to the internal DAC with a bit of a step up in resolution. By contrast, the Bifrost MB when paired to the Euterpe sounds a bit warmer and thicker than either the internal dac or the Swing. Overall, I was impressed with the internal dac implementation and surprised that the differences between the 9018 and 9038 in the swing were not considerably larger. While some of the telltale signs of the ESS chip are still on display, the tubes do a good job at balancing what can be a cold, clinical, precise sound with a bit of needed warmth and smoothness.

Stock tubes offer good performance but can almost always be improved upon depending on the pairing involved. The Stock pre-amp tube lacks a bit of dynamic range when compared to others and could deceive the user into thinking the unit is also equally limited. The stock power tubes are less of an issue and when trading them out for other models, I found that the most obvious change was in the speed of bass presented.

Tube rolling offers several advantages, the first of which is tuning the noise floor. The Euterpe is fairly quiet (particularly for a SET) but can be made even more so by swapping in a 12au7 for the pre-amp tube. With the stock tube (12at7) I could hear a hiss when using sensitive iems. Most of the time it was only evident when music was off, but on a few like the Magaosi K5 it could be heard during playback. With a 12au7 (I used an easy to find Amperex Bugle Boy) dropped the noise floor to dead quiet with the K5, but did also reduce the usable volume range with the HD800s. For HD800s, tweaking the sound by swapping in better quality tubes improved the sound overall. My preference was a Brimar CV4024 with the GE 5-star 6201 coming in a close 2nd. These improved the dynamics and the tonality of the mids.

I have made several comments regarding improving the Euterpe which one might mistake for suggesting it doesn't sound good out of the box. That is absolutely untrue as I found the tonality of the Euterpe fantastic and the voicing was very good when paired with the HD800. SWMBO who usually ignores my gear and only occasionally listens to something to placate me put on the HD800 and listened to Fleetwood Mac - Go Insane and immediately turned to me and said "You should buy that one". What can I say, she has good taste even if marrying me might suggest to the contrary.

Conclusions:

I have to say at the outset, when you price a product at $1800 USD and you name it after the greek goddess of music and "giver of delight", you'd better deliver or the thud of your product hitting the floor is going to be deafening. I was skeptical that a device that was as much headphone stand as it was dac/amp really could deliver the goods. It was already hamstrung by using a Sabre DAC, and a lower end one at that, so I knew the Sabre glare would be on full display. Guess what, I was wrong. Yep, it happens. Tonality is gorgeous with none of the treble harshness I expected and with the appropriate tube swaps, the background is as quiet as I have heard in a SET. While the DAC doesn't quite wring out the detail of some others, it does a very respectable job and may be the best ESS 9018 implementation I have heard to date. The Euterpe is as emotional and expressive as it is gorgeous to look at. It really does seem to bring out the best in a recording and is more forgiving than I expected.

Power is very good while not being so high that it prevents use of IEMs or so low that big planars are a no-go. It is more versatile than many all in one units due to the use of the 12a_7 family of pre-amp tubes that let the end user vary the Mμ from 17 to 100 depending on which member of the family is in use. The design of the cabinetry to double as a headphone stand is also one of those things that is so simple its almost hard to believe it hasn't been done before (I know Kennerton did it and loaned it to Auris). It makes infinite sense and using well figured hardwoods makes the mixture of wood and glass as much art on the desk as it is functional.

I'll also admit that I took SWMBO's advice and bought the Euterpe so this one won't be leaving my collection. That is probably the largest complement I can give it.

Rankings are based on stock tube set. Adding higher quality tubes (particularly the pre-amp) can boost scores as much as a full point.

(Side note: This tour unit was damaged in shipping and the metal base plate pulled loose from the wood. I removed it as the unit did not sit level with the base attached. I feel compelled to state that the packing job and subsequent issue were not the fault of Auris as it was shipped in something other than the original packing and mishandled by the Freight company as the box appears to have either conveyor or tire tracks on it).

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Been awhile since I’ve made an appearance in the review scene and what better way to come back after an extended hiatus than with a product such as this wonderfully sophisticated looking Auris Euterpe (pronounced you-turp)? Before I jump into the review, allow me to give a heartfelt thanks to my friend Mshenay for bringing this product to my attention to review.





The Opening Experience



I was given this unit in a generic box after an audio meet. Therefore I will not include thoughts or review of the unboxing because I was unable to experience a “real” one.




Construction

       

The build quality of this rather petite combi unit is remarkably beautiful. Boasting real wood side panels that are hand polished, the appearance of the Euterpe will likely complement the design of any location it’s placed in. The body and base of the Euterpe is made from a black aluminum like material that only complements the dark wood sides. Though these are very premium materials, the weight of the Euterpe makes me strongly advise to place this in an area where the drop risk is minimalized (though I don’t recommend dropping ANY piece of equipment) because I don’t believe the Euterpe would fair well if an accident were to happen. An interesting part of the Auris Euterpe that I believe may go unappreciated is the separation of the unit and power supply unit (PSU). Auris deciding to go with this design not only reduces the physical size of the Euterpe but it also reduces noise and interference. Something that I’m personally happy to see is the power interconnect cable is respectably thick and seemingly well shielded to further reduce external noise and interference, it also looks pretty nice as well.

Going over the more specifics of the design and build, the top of the unit boasts only the 3 tubes (2 PL95 and 1 ECC81). Moving towards the front of the unit you’ve the amazingly buttery smooth volume dial, that’s as linear and responsive in its movement as any volume knob I’ve ever felt before, the brand and unit name, source & impedance selector switch, and the single ¼” heapdhone jack. Finishing off with the back of the unit we’ve the analogue input and output ports, another brand and model logo, misc warnings, the digital USB input port and finally the power input port.

Auris definitely focused on a simplistic and straight forward design with their Euterpe headphone amp. Focusing solely on a single headphone output as well as not offering a balanced configuration is definitely something I don’t see too much of today. Overall, the Euterpe is however built very solidly and representative of its $1,700 asking price.




Specifications (copied directly from the product website)






Sound

   

Probably the most important thing of an amplifier (or in this case a combi unit) is how well does it produce and transmit the information to your desired headphone device? The name Euterpe is derived from the Greek Goddess of music and the giver of delight as well as being one of the nine Muses. As with Auris’ interpretation I will say that I enjoyed my experience with it. Seeing the tubes on the top I was believing that it would share a typical tube sound but that’s not the case. The Euterpe is a very transparent amp that, at least to my ears, offered little to no coloration to the music that I was listening to. Despite the amp pushing out less than a watt of power, it has very impressive dynamics and control of the headphones. Now, to disclaim, I no longer have any really difficult to drive headphones with my most “hardest” one being my HD650’s but I don’t feel that the Euterpe had any difficulties allowing the HD650 the ability to perform its best.

The thing I was most impressed with during my time with the Euterpe was its DAC. The detail retrieval that I got was very impressive and could rival that of dacs costing almost this much by themselves or at the very least hold its own against $1,000 stand alones. Similar to the amp, I also felt that the dac was also very uncolored and did nothing but portray the source material as accurately as it could. Though that may not be what I personally seek out in my equipment it most certainly fits the bill of what traditional audiophiles seek.

Going back to the dynamics that I mentioned earlier, the Auris Euterpe, if I could only list one thing that it excels at, I would have to say it’s that. From the softest of whispers to the booming bass hits, the Euterpe’s ability to showcase them elegant and with such control certainly has impressed me. A negative I have noticed however is that the soundstage is smaller when compared to my AT-HA5000-PS Audio DL3 and/or Sennheiser HDVD800. It was by no means up and in your face but I immediately noticed that everything sounded a fair bit closer than what I’ve become used to from my personal rigs.


Conclusion




The Euterpe is named after the Greek Goddess of music and the bringer of delight. I was overall delighted during my time with the unit but I can’t say that I’m going to feel a yearning to experience it again, it just didn’t fit my personal tastes as to what I look for in an amp/dac/combi. Also, I fear that the very small amount of power output in respects to other products in this price range, and even much less, makes it a hard push especially when some users have reasonably stubborn headphones to power. The fact that the Euterpe doesn’t come with a balanced option didn’t make a lick of difference to me and I only need a single headphone output as well. The takeaway that will stick with me is the beautiful dynamics that the Euterpe entranced me with. The elegance that she presented and the finessing touch made this otherwise transparent combi almost an intimate experience.






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I don't often hand out five star ratings but I really feel Auris has nailed this product. An given their target market and overall performance I really do think this is on of those rare products that earns and deserves it's 5 star rating! The Euterpe is their newest all in one Dac Linear Tube Amp with PreAmp all in one an it's retailing in the US for $1700.



I heard it first at Axpona this year with my Mr.Speakers Aeon Flow Closed and right away I went straight to listening to it with a few other dynamics. An in those short few moments with my own Aeon Flow Closed and some ZMF Dynamics I could tell this was a game changer. I've yet to come across another non hybrid all in one tube design that pairs nicely with both my planarmagnetic Aeon Flow Closed and a ZMF, so this was one of the few products there that grabbed my attention!

Design and Build Quality

In terms of design though overall I felt the Auris team really designed this product for a more modern ever evolving marketplace, which makes sense. In speaking with the Auris team their goal is really to combine beautiful aesthetics with traditional audiophile fidelity in such a way to gain both the approval of those concerned with performance and those who look first at aesthetics! Both spousal personalities or varying members of the household as it were.

They create products that not only perform well technicality but also fit into a well designed existing living spaces within a home or office, spaces that have maybe in the past been inaccessible or rather unable to support space for some of the larger more industrial looking products that are abundant throughout the Audiophile Community and marketplace!

Euterpe is an all in one unit, so both a Dac, Preamp and Headphone amp with both digital and analog inputs. I had no issue feeding digital input into Euterpe from both my Cellphones, Tablets, Laptops and desktop computers. An best of all I didn't have to download a single driver! I also found it worked seamlessly with a variety of playback applications, from Tidal, to Spotifiy on Mobile jRiver and FooBar on desktop plus quite a few other video apps, platforms and programs!

The hardware itself is sandwiched between two beautiful pieces of hardwood with four metal bars at the top to protect the delicate tubes beneath. Really a beautiful marriage of function and aesthetics! Additionally the volume knob feels smooth and house the power switch within it's rational axis and each of the input jacks are solid with no wiggle.

That said again Euterpe is both pleasant to listen to, pleasant to look at and pleasant to own and integrate! As an all in one it takes up very little space, it also doubles as a headphone stand eliminating the need for more hardware in existing spaces and best of all it's powered by a dedicated linear power supply unit.

An what I love about the LPSU is the rather long cord it has, again the Auris team designed the product to be incredibly easy to work into existing spaces and having taken the unit to about 6 head fi meets I always found Euterpe to be the easiest product to get set up and tear down! Again very little fuss or effort is needed to get Euterpe up and running.

Sound Quality

Overall Euterpe is lean and transparent without a cold or dry presentation. I found it most similar to something like a Schiit Valhalla but with a bit more detail and slightly more natural tonality.

The only real issue I had with it's tonality was a slight top end emphasis evident with some of my brighter headphones like my Sony MDR V7 or Superlux HD 668B. But for the most part it was airy without coming across as bright.

It presented bass with a polite but evident authority without any emphasis or added weight and heft.

Mid-Range tonality was even and the envelope featured a slight emphasis on release, this emphasis really helped to maintain a rich fullness without coming off as thick or smeared. Additionally this slight emphasis allowed for a vivid attack and presence without sounding shouty.

Finally while it was often airy and well extend up top, though there were times where it was a touch overemphasized. While this helped darker headphones have a more lively presentation with brighter more "fun" sounding headphones some tracks were a bit too hot for my tastes. Still I had no issues enjoying all genres of music including Heavy Metal, though tracks that are mastered less than ideally or have some purposeful top end emphasis like Drum n Bass were again sometimes mildly fatiguing with some of my brighter headphones.

Details, dynamics and precision in the sound stage were excellent tho I find it best to draw comparisons to my existing equipment to really ground it's technical performance.

Dac/Amp Comparisons

Modi 3 & Schiit Lyr 3 with Electro Harmonix 6SN7


Overall I did find Euterpe had a cleaner more focused envelope

• Less added body or no emphasis on decay and sustain
• Natural but not "thick"

Compared to Lyr 3 and Modi 3 Euterpe was more resolving

• Of both texture in the lows and through the mids and top end
• Vibrator in stringed instruments and vocalists was cleaner
• Fret and string noise for larger stringed instruments and electric bass was more defined
• Able to more clearly discern pattern or "beat" shifts in drumming
• More vivid PRAT again able to resolve quicker more subtle changes in rhythm, pace and timing
• Better or more apparent micro detail or resolve of transients throughout the spectrum

Euterpe also presented a more defined and precise sense of both air or distance between instruments and musicians as well and placement of instruments within the audible space or "room" an often time it's slight top end emphasis helped to better define the sound of the recorded space as well as everyone/thing within it.

The only drawback to Euterpe VS Lyr 3 and Modi 3 was in the lows, one of the things I love about the Lyr 3 is the added heft and authority it brings! A real sense of power without sounding bloated, it makes even my HD 600 really KICK.

Planarmagnetic Headphone Pairings


That and one of the only faults of Euterpe is be all end all power, as much as I loved it with my Aeon Flow Closed and Hifiman HE 4XX it did slightly dull the overall dynamics of each of those headphones. Where as with more powerful hybrid tube designs like the Lyr 3 and Ember II I get a slightly fuller more robust dynamic range. Still unlike other non Hybrid tube design's I've heard in the past, Euterpe didn't soften the overall texture of individual instruments or smear in the bass with more efficient planars like Aeon Flow Closed and Hifiman HE 4XX. Plus these days with an abundance of more efficient and non traditional planarmagnetic designs like that of the Meze Empyrean I don't see this lack of power as a huge problem. Though owners of more traditional planarmagnetics like Hifiman HE 6 or something like my own Hifiman HE 560 V1 and 2012 PreFazor Audeze LCD 2 will find the more powerful line of dedicated amplifiers offered by Auris to bring out the full potential in those less efficient more difficult to drive headphones.

JDS Labs EL Dac & Ember II [With Noise Nuke] + Heavy Modded SET Tube


Again the lack of power was evident for less efficient planars when compared to the Ember II , but as with the previous comparison Euterpe brought a more detailed presentation with overall better technicalities and more even tonality.

An actually I was surprised at how similar the voicing of Euterpe was to my own modded APPJ PA1502A SET and when I fed analog in from EL Dac to Euterpe [bypassing it's internal DAC] I found the performance between the two amps on par, though Euterpe is blacker during quite passages, more resistant to outside noise and hum with some low impedance dynamic headphones. That and it's build quality and literal between your fingers feel are vastly improved. Combined with it's much smaller the footprint and linear power-supply even as just an Amp Euterpe proves itself much more practical to own and operate than my own heavily modded SET.

Though my modded APPJ PA1502a SET Tube Amp was the result of months of research and tube rolling and some luck in terms of picking the right components to get the desired improvements I wanted over the rather lackluster stock performance. But again with Euterpe the performance is outstanding with 100% stock components so there's no guess work or time spent experimenting with tube rolling and the like.

RME ADI 2 + Amplification


While functionally different, I did find the overall technicalities of Euterpe to be only marginally better than RME ADI 2 with ATOM and my RME ADI 2. The real benefit of the Euterpe here though was it's slightly more natural tonality and ever so slightly more spacious presentation, and both amps have around the same power output and handle planarmagnetics similarly.

However the big difference here is the DAC Performance,



Compared to my "reference" system I did find Euterpe to fall slightly behind in terms of resolve, detail, tonality and sound stage precision. An frankly feeding the digital out of my RME ADI 2 into the analog of Euterpe was at best a marginal improvement. The only noticeable difference was less slightly fatigue when listening with my brightest headphone out of my own modded SET.

However in terms of costs my complete system is a a bit more than Euterpe and has some digital interface hardware in the form of a Schiit Etir feeding exclusively COAX into my DAC plus a lot of back-end power filtering hardware in the form of both power conditioners, aftermarket cables and a single massive stage LC filter "Noise Nuke" for use with my Ember II. Both amps also have modifications and tubes hand picked for my DAC and collection of headphones, I also have two different tubes for Ember II depending on the voicing or presentation of the planarmagnetic headphone I'm listening too.

My point here, in terms of be all end all resolve and detail it is possible to piece together something better for less than the cost of Euterpe. An many of you likely will, part of what I enjoy about this hobby is exploring, tinkering, modding and experimenting. Chasing down what ever I could to get the most of my system as a whole. With each incremental improvement carrying onward each time I drop in new components, but compared to just simply purchasing and owning Euterpe this method is hardly cost effective, quick or straight forward. Heck for this review I had it plugged right into an outlet on my wall using a regular or basic power cable. Still I'll touch on what I feel is the real value or Euterpe later in this review in my conclusion.

Dynamic Headphone Pairings

Overall I really felt Euterpe performs best and most consistently with dynamic Headphones especially those above 80 or so ohms. I did have some slight hum with 32 ohm Dynamics such as the Grado White but such hum wasn't always present with my own Symphones Magnum V7 Build, but my HD 800, HD 600 and AKG K702 had zero hum or noise what so ever! Euterpe proved to be entirely black and silent during any and all quite portions of music.

Still the output impedance is listed as "32-80" on the Low Gain setting and "150" for the High Gain setting, so I cannot say for sure how it will interact with all lower impedance dynamic drivers. I will say I didn't hear any audible low frequency boost as a result of high output impedance.



Aside from being ever so slightly bright with HD 800 and K702 on some less than perfect or hot recordings, I thoroughly enjoyed Euterpe with all my more resolving dynamics! I did find it to be much to bright with my Superlux HD 668B but that headphone has a lot of top end emphasis no matter what it's sourced from.

I in particular really loved the sense of depth Euterpe brought to my HD 600, with the Modi 3 and JDS Labs EL Dac systems the HD 600 sounded a bit shallower. However similar to my own reference system, I found Euterpe really allowed the HD 600 to present a more real sense of how the recorded space sounds.

I particularly enjoyed how far back the release and reverb of the cello reached into the room while listening to Sarah Jarosz's "Simple Twist of Fate."

With my HD 800 I appreciated how the Euterpe was able to bring both a sweetness and immediate sense of tactility to the guitar track in Marta Gomez's Celito Lindo.

I also loved how full yet still dynamic and explosive War from Explorations in Space and Time was with my AKG K702.

Really again the amp was quite transparent and maintained a consistent presentation with a variety of dynamic headphones with some brightness only evident with a headphone that itself places some emphasis in the top end.

Conclusion
What I absolutely LOVE about Euterpe it's beautifully straight forward implementation within a space and effortlessly high fidelity presentation. When I started this hobby I worked around 30 or so hours and attended college, I had much more time to research and experiment.

These days I work around 70 hours a week, I'm no longer living with parents with just a tiny bedroom all to my self. Rather I've a full furnished apartment, a small dog and friends I like to entertain with little to no free time to spend reading and researching online like I used to. Granted the young college kid I was continued on in life and eventually worked to furnish an entire dedicated room for all my Gear. But had I started this hobby now at this point in my life I likely would have gravitated to a cheaper single bedroom apartment with a bigger kitchen and purchased Euterpe for it's beautiful wood finish alone. An in my eye's the real value in Euterpe is as an all in one, it's beautifully assembled, and it fits right into an existing multi media system. In my own home I can feed analog line in from the digital receiver partnered with my TV and use the Pre-Amp to function alongside my 2.1 Sound System to enjoy movies and television and also run the digital connection out form my laptop and tablet to enjoy my high-res music collection.

I don't quite feel it's suited to those of you with large collections of headphones each needing vastly different amplification needs. Nor those of you who like to tinker, mod and experiment. However I am confident that for those of you who love music, the design and layout of your home as it is but and are still interested in high fidelity play back but don't have the time, nor space to piece together large complex multi-component systems Euterpe is the perfect all in one. It's overall transparent presentation pairs well with many of the well established high fidelity dynamics, such as those form the ZMF and many of the newest cutting edge planarmagnets like Empyrean. Add in it's simple plug and play USB interface and you'll be hard pressed to piece together a better system without having to devote the needed time, expense and space to house a complex and well matched system of individual components!