There’s something about a Class A/B amp.
Do you remember the old Aqua Velva TV commercials? The ones that aired during breaks on the Lawrence Welk Show that went a little something like this:
[Man’s face full screen]
“Mmm. How close.” Says a woman who’s mostly off screen while her hand strokes the side of the man’s face.
“It’s silicon close.” the man responds.
“How smooth.” Says the same woman who’s mostly off screen while her hand strokes the other side of the same man’s face.
“It’s silicon smooth.” He says with a wink.
Then Mamie Van Doren sings the closer, “There’s something about an Aqua Velva man.”
The Atoll SDA300 Signature relies on its MOS-FET power stage to deliver 150 Watts into 8 Ohms and 280W into 4 and as we know, metal–oxide–semiconductor field-effect transistors (MOS-FETs) are made with. . .silicon. Smooth. Silicon smooth. Inside reside a pair of 340 VA toroidal transformers that take up a lot of real estate, nice, and as you can see the left and right “double push pull” MOS-FET power stages reside along the left and right heat-sink’d sides of the chassis. Eight 6800 μF low ESR filter capacitors made to Atoll’s specs are covered with a sheet of thick metal foil to keep stray noise out.
The preamp stage runs in Class A with no feedback employed, while the internal DAC is based on the Burr Brown PCM1792 converter fed from the Roon Ready and DLNA/UPnP compatible Ethernet input or any one of four digital inputs (2x Coax, 2x Toslink). There are also a pair of digital outputs (Coax, Toslink), 2 USB-A inputs, one back one up front, for connecting USB storage, 2x analog RCA inputs, a Pre Out, 1 Trigger output, and a single set of binding posts located on either side of the amp and close to the left and right power output stages. You can also connect to the SDA300 Signature via WiFi or Bluetooth and control playback with the free Atoll Signature 2 app for Android and iOS, your UPnP app of choice, Audirvana or Roon.
I went with Roon throughout the review minus a brief walk around the Atoll app which was easy and intuitive to use. For people not interested in everything Roon has to offer, and I wouldn’t want to live without, the free Atoll app with access to Qobuz, Tidal, and of course network- or USB-based files is a nice option. You can also run app direct with Tidal Connect or Spotify Connect. There are also a number useful functions available through the Atoll app including checking for and initiating Firmware updates, choosing a language (English, German, Spanish, French, Italian, Nederland, Polish, Portuguese, Russian), renaming inputs, and more. I recommend a look through the extensive SDA300 manual for the complete picture.
The SDA300’s thick aluminum front panel, which comes in black or silver, has a nice bright and colorful 5″ TFT LED display (800*480) dead center joined by a 1/4” headphone jack, matching knobs for menu navigation (left) and volume/On/Sleep (right), a Return/Back button for menu navigation, and the aforementioned USB-A input. The included Atoll remote offers all of these functions and much more, with the ability to control other Atoll devices like one of their CD Players. Here’s the complete list of on screen options—Playlists, Internet Radio, USB, Media Server, Qobuz, Tidal, Deezer, Amazon Music, HighResAudio, Spotify, Bluetooth, Line 1 and 2, Coaxial 1 and 2, Optical 1 and 2, Settings.
I’m a fan of the subtle lines, hole patterns up top and running down either side, curved corners and the general fit and finish of the Atoll SDA300 Signature that looks and feels elegant. Its 40+ lbs, remember those toroidal transformers, also adds to the SDA300’s gravitas.
Atoll was founded in 1997 by Stephane and Emmanuel Dubreuil and their lineup currently consists of 41 products which are all hand made in the company’s Normandy, France facility while many of the parts that go into and around Atoll gear are sourced within France. From the company website:
Our production is completely carried out on-site. We also subcontract specific parts in France, which account for almost 80% of the product’s value. The chassis is manufactured in Bretagne, the aluminium front facades are in Lorraine, the printed circuits are in Pays Basque, the transformers are in the Rhône region, and the packaging is in Normandy. This approach provides reliable and consistent quality, quick response times, and excellent flexibility in meeting demand.
I appreciate this kind of attention to quality and control as well Atoll’s long hifi history. I also appreciate just how all of these things—experience, parts, construction, function—translated into a rich, that lovely Class A/B heft, refined powerful performance. I also love the idea of a streaming integrated amp, much more than an integrated with a DAC which always feels one function away from being complete, and the Atoll SDA300 Signature has become a favorite example of a complete package that delivers pure sonic joy.
I mainly paired the Atoll SDA300 Signature with the Barn resident DeVore Fidelity O/96 (review), the recently arrived Gauder Akustik Capello 100 speakers (more info), and the recently reviewed Vienna Acoustics Limited Edition Bach Ultimates (review), three very different species of speaker and the SDA300 Signature drove each one with the same rich, powerful, and refined sound with excellent bass control and nary a hint of harsh. Smooth. (see full system and Barn details)
Julia Holter’s 2024 release Something in the Room She Moves is another gem from Holter’s seemingly endless imagination feeling and sounding even more unbridled, damn near weightless, than her previous albums. “I was trying to create a world that’s fluid-sounding, waterlike, evoking the body’s internal sound world,” shared Holter and I’d say she succeeded and then some as listening through Something in the Room.. feels like floating in a deep, warm and weightless world. With the Atoll SDA300 Signature driving the Gauder Akustik Capello 100s, which I’ll have a lot to talk about in that review, the Barn’s B-Side filled up and nearly overflowed with the lovely fluid sounds of Something in the Room She Moves, offering the kind of deep unfettered listening I’ve come to associate with more gear and more cost. While it may seem a bit of a price mismatch pairing the $5500 Atoll with the $26k+ Gauder Akustiks, the system performance said otherwise. Nice.
One quiet morning, it’s always quiet out here but with a light dusting of snow it seemed even stiller, I was inspired to re-visit Satie’s piano works after being inspired by an Instagram video post of Jacques Février performing “Gymnopédie No. 1” from 1966. I went with my old Satie standby Aldo Ciccolini and settled down for an album-length listen. Here, with the Atoll driving the DeVore’s, piano resounded in Barn with near live-like force, voice, and sparkle with Ciccolini’s light dance of a touch adding just the right amount of smile to these playful, lovely works. And I was so taken with Satie and this lovely simple system I let Roon Radio take control and was swept away by a stream of classical delights including Celedonio Romero’s Guitar Recital and his masterful walk around variations on a theme by Handel, a sweet taste of Debussy from Clair de lune, “Cyprès et Lauriers, Op. 156” from Saint-Saëns, and on and on for hours.
When I say I listen to a lot of music, I mean it and I let the Atoll SDA300 Signature with the O/96 and for the last week or so the Capello 100 fill the Barn with days and nights and weeks of all manner of music and the only system-related thoughts that intruded were amazement at just how well the SDA300 Signature reproduced everything. Again, for its price I’d call this level of performance unexpected and delightful. Bravo! While I also enjoyed the SDA300/Vienna Bach pairing, I felt these otherwise fine speakers left too much of the SDA300’s talents on the table. Or to say it another way, when building a (simple) system around the Atoll I recommend looking well upstream for appropriate partners.
Sometimes you just don’t know, and I certainly didn’t see my near infatuation with Hurray for the Rift Raff’s The Past Is till Alive coming. I’ve seen Alynda Segarra’s music referred to as folk-punk and I won’t argue the point but the real appeal, for me, here is their way with stories told in song. Is that folk? Blues? Country? Punk? In any case, The Past Is Still Alive has been acting as my soundtrack for many months, soon after its February release on Nonesuch Records, and its words and movements have been twisting and turning in my head, occasionally spilling out of my mouth. Here’s a secret—when a system is singing out true I have a tendency to sit up straight(er), lean my head back, tilt my chin upward, and sing along. It’s nearly a reflex action and the Atoll SDA300 Signature had me belting out as many tunes as I can remember.
Acoustic and electric guitar, dobro, bass, organs, piano, fiddle, sax, pedal steel, drums and more form the foundation over which Segarra tells their tales and each system the Atoll was in, whether driving the DeVore O/96 or the Gauder Akustik Capello 100, presented each voice of each instrument perfectly convincingly and what’s more the whole ensemble rang out with the kind of rich, full, and fluid voice that feels so present you just can’t help but sing along. At least that’s the way enjoying music at this level works for me. It’s as if hearing the sound of Segarra’s voice along with this lovely cast of supporting characters that include Brad Cook, Anjimile, Conor Oberst, and another favorite S.G. Goodman reached so effortlessly past reproduction and inside me I nearly felt part of the production.
Kevin Richard Martin and KMRU’s Disconnect, released on Phantom Limb back in June, digs deep, subterranean, which should come as no surprise seeing as Martin, aka The Bug and King Midas Sound, builds his sonic landscapes from well below the ground, up. Without giving too much away, the Gauder Akustik Capello 100 can reproduce deep deep bass with ease and this record with the Atoll SDA300 Signature doing the driving rattled every rattly Barn bit. And there’s a lot in here that rattles. This system also created an immense system defying soundscape with plenty of air, space, and refinement that made this music feel big city big and darker and more menacing than a Tarkovsky nightmare.
From the liner notes:
The record is just as deep, expressive, and arresting as we can expect from Kevin Richard Martin, following his acclaimed rescore of Solaris (released in 2021 on Phantom Limb) and a handful of self-released solo albums that explore a sound just as heavy as The Bug but at a menacingly slower pace. And it is just as evocative and unique as Kamaru’s KMRU canon, each object delicately and purposefully placed so the timbral mosaic builds with shimmering and hypnotic beauty.
And the Atoll’s strengths played this delicately and purposefully placed timbral mosaic with what felt like every last ounce of its shimmering and hypnotic beauty in tact. Breathtaking.
I let Mabe Fratti’s Sentir Que No Sabes tell me about the Atoll’s headphone driving ability with the Barn resident Meze Audio 109 PROs whispering in my ears. This is another favorite record from 2024 for its delicate, intricate, cello and vocals driven wonders.
This is music as rich and varied as a tropical jungle and the SDA300/109 PRO combo offered a similarly deep, rich and rewarding sound as heard through loudspeakers. We know, you & me, I don’t spend a lot of time listening through headphones as I enjoy, relish really, having music fill the Barn and me with vastness. So you can take the fact that I enjoyed my headphone time with the SDA300 Signature within that context.
In terms of comparisons, there aren’t any from my list of Favorites that offer the streaming capabilities of the SDA300 Signature coupled with its superb sonic performance and I have to go up that list of Favorites, all the way up to my Leben CS600x, before I pause to reflect which I’d rather choose to live with. I’ll talk a bit about that Luxman L-505Z integrated in its review and how it stacks up, sound wise, to the Atoll but seeing as the Luxman has a phono stage and no streaming, it’s going to be an apples to mash potatoes kinda comparison…
Rich, refined, and deeply rewarding. And smooth. And by rich, I’m talking about the winning combination of tone, texture, and heft that imbues reproduced music with earthy appeal. Weighty in the deepest sense of the word when talking about the enjoyment of music. The Atoll SDA300 Signature offers all of these things and I don’t know of another streaming integrated amplifier anywhere near its price I can recommend with more enthusiasm or confidence. Bravo!
Atoll SDA300 Signature
Price: $5500
Company Website: Atoll Electronics
US Distributor Website: Audio Excellent
Technical Data
Power supply: 892,2 VA
Wrms/channel/8Ω: 2×150 W
Wrms/channel/4Ω: 2×280 W
Total of capacitors: 65 800 µF
Input impedance: 220 kΩ
Maximum input level: 3,5 Vrms
Distortion at 1 kHz: 0,05%
Bandwidth: 5 Hz – 150 kHz
Rising time: 1,3 µs
Sensitivity: 350 mV
Dynamic: 129 dB
Signal/Noise ratio: 129 dB
D/A converter: Burr-Brown PCM1792
Dimensions: 440×365×103 mm
Weight: 19 Kg
