Boulder 866 integrated amplifier Page 2

With the decision to use equipment supports left up to me, I placed Nordost Titanium Sort Kones on one of the top shelves of my Grand Prix Monza double tier equipment rack and put the 866 on top of those. Nordost Odin 2 XLR cabling conveyed an analog signal from the Rossini.

Then I plotted my review strategy. First, I'd spend a long time listening to the 866 fed by the Rossini DAC/Rossini Clock. Then I'd compare the sound with the Rossini DAC/Clock to that with the 866's internal DAC. For high-rez streaming, I stuck with Qobuz because Boulder's DAC does not decode MQA and all of Tidal's high-rez content is in that format.

For comparison, I imposed upon my friend Dr. Gary Forbes to lend me his Krell K-300i integrated ($7500, or $8500 with optional DAC) that he bought after reading my review. I trust my aural memory, but there have been many significant changes to my streaming setup, room and power treatment, and equipment supports since the Krell was here. To ensure fairness, I needed a refresher.

Scaling the heights
The 866 proved as solid and reliable as it looks. There were just a few glitches. When I switched inputs from "Analog" to "Network," the 866 reverted to standby and required a few on/standby/on sequences before everything synched. Once I got hip to that process, I began putting the unit into standby before changing inputs. Since most users aren't going to be switching DACs back and forth every day or two—a reviewer's experience is unique—this won't prove a real-world encumbrance.

I appreciate warm sound, but acoustic music does not sound overtly "warm" in the various halls I frequent. The electronics and cabling I favor most complement my Wilson Alexia 2 loudspeakers in terms of neutrality, believability, and transparency; they are not overly warm. The Boulder 866 integrated scored a solid A in areas I value most.


After reading a rave review of Israeli-born pianist Shai Maestro's Human (24/88.2 FLAC, ECM/Qobuz), I cued it up on Roon/Qobuz and listened to a few tracks using the dCS Rossini DAC. The sound was wonderfully rich on Maestro's "Time" and "Mystery and Illusions"; indeed, I found the sound as captivating as the music. Depth may not have been as clearly defined nor bass as strong and tight as through my D'Agostino Progression monoblock/Momentum HD preamp reference, which together cost almost six times as much (plus the cost of extra cabling), but timbres and transparency were comparable to the best I've heard from my system.

I ate up the beautiful midrange on Rickie Lee Jones's subversive take on "Sympathy for the Devil" from The Devil You Know (16/44.1 FLAC file, Concord); hers is a devil you want to pal around with, come what may. I was enamored of the natural sweetness, radiance, and warmth of soprano Elly Ameling singing about the stars of heaven in Schubert's "Die Sterne," with Dalton Baldwin on piano, on the indispensable four-CD anthology The Artistry of Elly Ameling (16/44.1 FLAC, Philips/Qobuz). Jones and Ameling's very different voices sounded just as I expected them to sound. Next, lured back to the devil's territory by the final "Sacrificial Dance" from Ludovic Morlot and the Seattle Symphony's take on Stravinsky's The Rite of Spring (24/96 WAV file, Seattle Symphony Media), I again found colors spot-on. I may not have heard shake-the-floorboards bass (footnote 4), but the piccolo had realistic bite, the rhythms were firm, and the music was thrilling.

I wasn't aware of any internal ontological struggle between heaven and hell during the review period, save for a brief descent into the netherworld of internet non-connectivity. But after Stravinsky's pseudo-pagan ritual, I found myself called by the heavenly final movement of Mahler's Symphony No.4 in G major. This delicious music, which depicts a child's version of heaven, demands a soprano who can describe a gluttonous feast in tones of total innocence. No recording I've heard has topped the one made by soprano Kathleen Battle and the Vienna Philharmonic under Lorin Maazel, especially as remastered on Classic Kathleen Battle: A Portrait (16/44.1 FLAC, Sony/Tidal).

Through the Boulder 866, Battle and the widely spaced instruments behind her sounded right. I was able to hear her emphasis on core tones, beefing up her slender sound. When she transitioned to her clear, luminous upper range, the Boulder enabled me to bask in the uncommon purity of her angelic sound (footnote 5).

Time and again, the 866 made me happy. It couldn't produce a soundstage as wide as my big monoblocks do—no integrated I've heard here has been able to do so. Its bass wasn't as firm as that of more powerful amplifiers, and it couldn't deliver ultimate transparency. Engineer Bud Graham captured the spaciousness and glow of the hall on this recording, positioning the orchestra in a deep, coherent soundfield. I could not hear the full resonance of Vienna's Musikverein, the magical silence between notes, or the depth relationship between the separately miked soloist standing to the left of center, the instruments spread out behind her. Images floated in space rather than finding an anchor in a definable venue, as I could with my far more expensive reference components. But the music's essential color palette, and its message, were as captivating as they are with any equipment.

On "Trouble Is a Man," from her new album Clique (32/352.8 WAV file, Impex), Patricia Barber sounded as cool and assured as ever. Colors were perfect on Chris Thile, Edgar Meyer, and Yo-Yo Ma's Bach Trios (24/96 WAV file, Nonesuch) and on Murray Perahia's smile-inducing piano performance of Handel's Harpsichord Suite in E, HWV 430, from Murray Perahia Plays Handel and Scarlatti (16/44.1 FLAC, Sony/Qobuz). I felt I could trust the Boulder 866 to be there for me, time after time, delivering sonic truth.


On the digital trail
With Roon as my playback software, I moved my Ethernet cable from the Rossini combo to the Boulder 866. As soon as I changed the 866's inputs to "Network," a previously unseen "Roon Ready" input appeared on the iPad running Roon Remote, and the brightly colored cover of whatever I had cued up appeared on the 866's display screen. I felt like I did many years ago as my grandmother and I sat in a huge uptown-Manhattan movie theater watching The Wizard of Oz for the first time, and the screen turned from black and white to Technicolor.

Color wasn't only on the 866's display; it was also in the music it made. The 866's DAC sounded far better than I expected a $1500 DAC to sound. On The Rite of Spring, the soundstage was surprisingly wide and tonalities were spot on. Pace and rhythm were a bit slower and less crisp than through my reference DAC and Clock (which cost more than 20 times as much), and the sound was a mite less airy and open. But the music was so engaging that I sat in wide-eyed disbelief.

When my friend Gary brought over the Krell, he asked to hear Catherine Russell's fabulous rendition of "I Let a Song Go Out of My Heart," from her album Bring It Back (24/88.2 FLAC/Qobuz). We compared the Boulder's DAC with my reference front-end amplified by the Boulder 866. The reference source delivered more air and texture and a silkier voice, but I loved the sound with Boulder's DAC.

Next, the Boston Modern Orchestra Project's new recording of John Adams's madcap Chamber Symphony (24/44.1 FLAC, Qobuz), which the Boulder DAC delivered with a wider soundstage than I expected from a 44.1kHz recording. The densely scored Chamber Symphony, which calls for six woodwinds, four strings, horn, trumpet, trombone, drum set, and synthesizer, starts with a stunning thwack on a cowbell that could propel somnolent audience members out of their seats. Its sequel, Son of Chamber Symphony, for 16 musicians, which is also on the recording, is even more colorful thanks to the added piano, thunder sheet, and a second violin.

Comparing the Boulder to the Krell K-300i was enlightening. Colors were spot-on and much the same, but the Krell illumined them with a seductively warm inner glow. With the Rossini as DAC, the Krell was airy, open, and deep. Its optional Roon-ready DAC decodes MQA, and its sound is quite transparent. Which presentation you prefer will depend on how you prefer to experience music.

Back to basecamp
The Boulder 866 integrated amplifier delivered one of the most straightforward and reliable presentations of any integrated I've had in-house. Its color palette was eminently satisfying, as was its ability to present music honestly, without editorializing. The quality of its optional DAC and its full-color display blew me away.

The 866 is a one-stop integrated that's made to uplift, not fatigue. It brought me hour after hour of happiness. Highly recommended.

Footnote 4: If your floorboards are shaking, you have a room-acoustics problem. But yeah, I know what he meant.—Jim Austin

Footnote 5: This one's for you, David Chesky.

Boulder Amplifiers, Inc.
255 S. Taylor Ave.
Louisville, CO 80027
(303) 495-2260 x116

georgehifi's picture

How nice it is to see extended frequency response and a pure untouched 10k square wave like this without the need of an Audio Precision auxiliary AUX-0025 passive low-pass filter to hide/mask the switching noise oscillations all over it. Like Class-D needs to make it look not even half as good as this, and with out the AP filter!! buzz saw comes to mind, but sadly that not shown anymore, as it's too visually bad for business.

Cheers George

RH's picture

- - - "I appreciate warm sound, but acoustic music does not sound overtly "warm" in the various halls I frequent. "

I'm not sure how exactly to interpret that part of the review. But from my perspective as someone obsessed with the differences between live and reproduced sound, one of the distinguishing characteristics to me of live acoustic sources is "warmth." The average sax, trumpet, trombone, even acoustic guitar, sounds so much bigger than on most audiophile playback systems I've heard. Most reproduction to me has a reductive, hardening effect on most acoustic sources. "Warmth" in terms of fullness of "body" and richness of harmonics is just what I hear in acoustic music vs reproduced, virtually wherever I am situated to the music, or in whatever hall I listen.

Of course, since essentially all reproduction is compromised in regards to reproducing true realism (especially if we are talking about symphonies!), it's a pick-your-compromise and we tend to zero in on the aspect of sound that strikes us as most consonant with reality. Some may zero in on the transient precision and dynamic presence of, say, some horn systems, others may find the more relaxed richness of another speaker gets at what they hear in real music. I tend toward (certain) tube amplification insofar as I hear a bit more of that roundness, body and relaxed warmth I pick up on when hearing live sources. YMMV of course...

brenro's picture

Save $6000 and buy a Krell K-300i.

Ortofan's picture

... Rotel Michi X3.

tonykaz's picture

Nice work, Mr.Jason!

The Boulder is probably a nice piece of gear but I'd still insist on a Round Volume knob, the bigger the better. I'd even like the power switch to be mounted behind the volume knob in an Old School way of things with the Volume knob acting as the OnOff control like an old Car Radio.

Does this Amp have a sloping Front Panel like the Pictures seem to show?

Anyway, nice work Jason,

Tony in Venice Florida

Anton's picture

It can compress to as little as four inches deep or expand to as much as 28 inches.

Front face angle is as you desire.

tonykaz's picture

Brilliant observation!

I wonder if they built it that way to save on the Dimensional Weight Shipping Formulations?

I have a bit of Vintage gear that mostly remains rather tiny but enlarges when the occasion arrises! I never show it to anyone, ( mostly out of embarrassment and because it ain't pretty ).

Tony in Venice Florida

Kal Rubinson's picture

It can compress to as little as four inches deep or expand to as much as 28 inches.

Does it move from Class A/B to pure Class A as it expands? :-)

Jason Victor Serinus's picture

a lot of us would be in a class above.

nomaslarge's picture

This does feel a little like one of those "damned with faint praise" reviews and the comparison to the k-300i is vague and leads one to believe that to the reviewer's ears it's really a tossup based on what you like (which obviously for most of us would lead to the conclusion of "I'll take the one that is $6k cheaper"). I know that JVS loved the k-300i and it was been very well reviewed elsewhere - I admit I've never heard it. But the K-300i is often compared to a unit I owned for a while - the Naim Uniti Nova. I thought the Nova was impressive and enjoyed it more than I thought I would given that when I got it I was coming from a pricey VAC tube rig. I briefly considered trying the K-300i while I had the Nova and spoke to a few people with experience of both units who felt that it would be a sideways move unless I really needed the extra power of the Krell. I then went to a Pass Int25 which to my ears was just in a different class than the Nova - I won't bore you with the details, I'll just leave it at the fact that for me this wasn't even a close comparison in terms of what these amps were capable of. And now recently I got a Boulder 866, which I find to be in an altogether different class than the Int25, by at least as significant a margin as I found the Pass to be superior to the Naim. The Boulder feels to me like it competes with some of the high-dollar separates that I've owned in the past. Because of the surprisingly high performance of the DAC, it almost seems like a bargain at its price. Of course, the commutative property doesn't always hold in audio... but for these reasons I am skeptical that the 866 and the K-300i are on a level playing field with only one's preferences and about $6k sticker price separating them.

Salva69's picture

Jason Victor Serinus could be a good music reviewer but as a gear reviewer, I feel sorry to say that he is the most boring I've ever read in the pages of Stereophile.

nomaslarge's picture

I find JVS to be an excellent writer but I don't get the sense the 866 inspired him very much which is... you know... the way it is sometimes with gear. Who knows why it is that some pieces excite us and others don't. The 866 has excited me quite a bit which is why I left my earlier comment.

tonykaz's picture

Music is a delightful life companion, sharing that experience is a nice gift to us all.

Thank you,

Tony in Venice Florida