Solid State Preamp Reviews

"There's only one way to design a D/A converter correctly. What is really, really crucial is the regulation loop in the circuit that compares the 'digital' voltage to the analog voltage from the power supply. In other products, I sometimes see cheap capacitors that are not well-suited to the application but were chosen to cut costs. Those parts were probably determined by the price-minded guys in the Controller Department. So, we're very careful about what parts to use where. Sometimes we must use a special ceramic capacitor, and sometimes a far more expensive foil capacitor. Our bottom line is not achieving the best price but rather than best price–performance (sound) ratio. We never compromise sound quality by substituting less suitable parts."

I asked Größler why the 151 MK2 doesn't directly convert or output PCM above 24/192 and why it didn't keep DSD data in the DSD realm, instead converting it to 24/192 PCM.

"Serial data streaming like DSD and packed data transport like PCM are just different ways of presenting the exact same sort of information. That's why if you find differences, they're not technology-related; they're customer and business-related.

"It's all about the physics. Sometimes the decimation filters that resampling requires have a sound due to preringing and postringing. A perfect impulse doesn't have preringing and postringing, but in the digital world, it happens naturally. So, you might have special digital filters that move the preringing to postringing. Sometimes you can hear it. Due to the heavy dynamics and fine details of classical music, some formats may sound better than others, but that's only because the mathematics work better with certain filters.

"We will eventually be able to support higher bit rates and sampling rates, but the technology isn't finalized on our end. Regardless, I don't think perceived sound differences are due to the technology. I think some labels make one format sound better than another so you can spend more."

Simplicity?
"We never make products intentionally complex," Größler told me. "We don't over-complicate." Nonetheless, I found some of the 151 MK2's many functions a challenge to master.

Some of my initial confusion arose not from a dearth of information but rather from its abundance. The unit arrived with four impressive English-language manuals: an iPad App User Interface (42 pages), an Operational Manual (32 pages), a Web Interface manual (42 pages), and a Tidal Owner's Manual (10 pages). The language was simple and clear, the graphics abundant, but the options were dizzyingly numerous. Manuals often referred to each other. At one point, I put the iPad atop the unit (which was on the rack's top shelf), put one manual beside it, held another in my hands, and attempted to go between pages in different manuals. Then everything tumbled to the floor. That's when I put out calls for help via email and WhatsApp, took a break, and addressed my frustration by walking the dogs, running three miles, and eating everything in the refrigerator.

After those consultations (via WhatsApp), I felt ready to proceed. I moved my Ethernet cable from the dCS Rossini DAC to the Burmester, attached balanced interconnects from its XLR outputs to the inputs of my balanced-only D'Agostino Progression M550 monos, and adjusted the Burmester's audio output voltage to match the gain of the Progression M550s (footnote 3).

When it was time to evaluate the 151 MK2 Musiccenter as music server/DAC with an external preamp, I reconnected my D'Agostino monoblocks to my D'Agostino Momentum HD preamp, connected balanced interconnects from the preamp's inputs to the Burmester's balanced outputs, and changed the Burmester's audio settings to "fixed volume."

Finally, to evaluate the 151 MK2 as a music server only, I restored the balanced interconnects to their normal positions and ran a single S/PDIF digital cable from the Burmester to the dCS Rossini. I heeded Burmester's warning to turn off every component before switching cables, lest damage or unwanted pops from the speakers occur. Following directions, I updated the 151 MK2 Musiccenter's firmware.

In addition to playing files loaded into internal memory and streamed from Qobuz and Tidal, I evaluated how the sound of a Red Book CD ripped to internal storage compared to its 16/44.1 stream.

Ingesting music
Like most music servers, the Burmester works best with a music library that's already optimized and organized. Like most music servers, it sometimes struggles in ingesting new music.

When Burmester's software correctly identified music added to the 151 MK2 Musiccenter's internal SSD, playback proceeded smoothly. Once, though, I attempted to add 52 albums at once from a USB stick. These files were organized in the usual way, each album in its own folder. Burmester's software, though, seemed to ignore the file structure, aggregating music in long lists of tracks under the labels "Various Artists" and "Unknown." Sometimes, when folder structure was respected, cover photos stored in the same folder as the music failed to display (footnote 4). Nor could I find a way to open pdf liner notes. If I knew a recording's contents, I could locate files and reconstitute/rename folders, but this took time.

The last recording I auditioned with the 151 MK2 Musiccenter, François-Xavier Roth and Les Siècles's marvelously played, otherworldly period-instrument rendition of Debussy's five-act opera Pelléas et Mélisande (24/96 WAV, Harmonia Mundi HMM 905352.54), challenged both the Burmester app and Roon, which I consider the state of the art in music-server software. Roon first: Although the opera's 38 music files were divided into three subfolders—CD 1, CD 2, and CD 3, with tracks within each labeled in sequence beginning with "01"—Roon ignored the subfolders, lumped everything together, and played all three "01" tracks before moving on to the three "02"s. In rapid succession, Mélisande was lost in the forest, seducing Pélleas, dead, and then lost again. An opera about reincarnation Debussy did not write. To hear what he intended, I needed to relabel the 38 files as "1-01" through "3-15" (footnote 5).

To import this opera into the Burmester, I loaded it on a USB stick all by itself. The folder structure was respected, but the device labeled the folder "Unknown" and displayed neither cover art nor liner notes. It was easy to add the opera title, but there still was no support for displaying liner notes from files.

Designer Stefan Größler described Burmester's approach to ingesting music: "When importing or playing music from external storage, we use the metadata provided in the music files. When the music is imported, the meta information is also transferred to the local database and can be edited by the user in the web UI. ... If the music library that is to be imported is well maintained and the tags are neat you are fine." If it's just files in a folder without metadata, it may not work as well. "The 151 relies on tags, folder structure, and filenames."

Once the files were located and the folders identified, the Burmester 151 MK2 performed flawlessly. I easily added music to playlists and played whichever tracks I wished. And they sounded mighty fine.

The joys of listening
With the 151 MK2 Musiccenter operating in its full capacity as a server/streamer/DAC with volume control, I ripped one of my favorite CDs, Murray Perahia Plays Handel and Scarlatti (Sony SK62785), to its SSD. The process went smoothly. The app located the correct cover art in Burmester's database and displayed it, and the tracks were displayed correctly. With the app playing the ripped files, I found the sound more vivid and engaging than the sound of the Qobuz stream. As a CD ripper and playback system, the Burmester 151 MK2 Musiccenter excels. The 151 MK2 can also play back CDs without ripping them.

To prepare for a concert I would review for Classical Voice North America, I streamed Mozart's Sonata in B-flat major, K.454, from Pinchas Zukerman and Marc Neikrug's Sony recording, Mozart: The Complete Sonatas for Violin and Piano (16/44.1 FLAC, Sony/Tidal). Air and spaciousness were excellent, the soundstage was wide, and the music flowed, warm and involving.

The Burmester's delivery of the B-flat major's gorgeous second movement andante from these artists' hands transformed it into one of the most serene, "I could die right now and go to heaven smiling" pieces of music I've heard. It touched me far more than the live performance I heard two nights later from an acoustically ideal seat. A finer compliment to a music playback system cannot be paid.

Next, I revisited a recording I reviewed in the April 2022 issue, Alina Ibragimova and Cédric Tiberghien's new Mendelssohn: Violin Sonatas (Hyperion CDA68322, 24/96 WAV). The violin sounded liquid and free, and the energy of the two players projected with perfection. The piano sound, though, was somewhat flat, the colors somewhat muted.

An entirely different sound world awaited on Jonathan Cohen and Arcangelo's recent period-instrument recording of Bach Cantatas Nos.35 & 169 with countertenor Iestyn Davies (Hyperion CDA68375, 24/96 WAV). Although reproduction lacked the last iota of pristine silence between notes, the glorious sounds of baroque orchestra and voice filled me with joy.

Switching musical gears: Bass was excellent on my old standby, "Electrified II" from Yello's Toy (24/48 FLAC), but there was again a bit of gray between each gut-shaking note. Ditto for the fabulous bass on Martin Garrix's single, Animals (Qobuz 16/44.1 FLAC), which I found on the Editorial Tracks from Stereophile playlist. This recording and Rickie Lee Jones's "Sympathy for the Devil," from The Devil You Know (Tidal 16/44.1 FLAC), lacked only the last iota of color and transparency.

When I bypassed the 151 MK2 Musiccenter's volume control and sent the music through the D'Agostino Momentum HD preamp, the soundstage moved farther back and opened wider. On the Mendelssohn, the delicacy and nuance of Ibragimova's touch and the overtones of her violin filled the space. The sound was smoother, and color increased. I'd expect no less from a stand-alone preamp costing $15,000 more than the multifunction Musiccenter by itself, but the comparison helped put the 151 MK2's excellence in perspective and explained why some owners of the product pair it with an external preamp.

A delightful surprise came when I switched from the Burmester's internal DAC to the dCS Rossini DAC with external clock. This left the 151 MK2 Musiccenter functioning solely as a server/streamer. While the Rossini combo excelled in communicating subtle shifts in timbre, undertones and overtones, color, texture, and space, the changes were far less dramatic than the shift to an external preamp.

Every time I switched DACs back and forth, my appreciation for the excellence of the Musiccenter's D/A conversion and essential sound increased. On "You'd Be So Nice to Come Home To" from Art Pepper Meets the Rhythm Section (16/44.1 FLAC, OJC/Tidal), the external preamp noticeably increased color contrasts, transparency, smoothness, dynamics, weight, and warmth. If I may turn the estimable Gertrude Stein's most memorable phrase about my old hometown of Oakland, California, on its ear, there was more there there.

Switching DACs further increased smoothness and bass weight, but the improvements were far more subtle. When I compared DACs on Les Siècles's aforementioned Pelléas et Mélisande, the Burmester's internal DAC yielded voices almost as full, air almost as good, and bass that in this case was just as good. The Rossini lent an extra level of natural grace and air, at considerable extra cost. As I think back to all the stand-alone DACs I've heard that come close to the DAC's estimated share of the 151 MK2 Musiccenter's price, I have no qualms rating it among the best.

Conclusion
To repeat something chief designer Größler declared during our chat, which I already reported, above: "We want music to sound just as the artist intended. We aim for the essence—in German we call it 'Substanz'—in music."

Burmester's 151 MK2 Musiccenter delivers on its designer's promise. When paired with a quality external preamp, it facilitates all the joys, sorrows, sadness, and jubilation music offers. Music lovers who retain their love for silver discs will find them sounding even better when ripped to the unit's 2TB SSD, and those accustomed to file playback and streaming will find the Musiccenter's multifunction, multipurpose excellence a one-stop avenue to bliss. Through the 151 MK2 Musiccenter, music sings supreme.

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Footnote 3: Burmester's description in the manual is imprecise, seeming to equate power with gain. It's simply an output-voltage setting.

Footnote 4: It seems they must be titled a certain way.

Footnote 5: This is a common problem with music server software generally. Once the music is ingested, everything works fine, but ingesting music and setting up a library is an error-prone process. Fixing it up—in my experience at least—requires a certain amount of competence in information technology. When I ripped my CD library several years ago and ingested it into Roon, I spent many hours editing metadata. Even though I observed Roon's suggested best practices, some files—especially multi-CD boxed sets that collected several works on a single disc—stubbornly resisted my efforts. One boxed set of Janácek operas took weeks to get right.—Jim Austin