Boulder 812 DAC/Preamp

What did I glean from my queries? First, like the Boulder 866 the 812 employs a Raspberry Pi 4B as its internet gateway device. As for its DAC section, it’s not a chip from AKM, ESS, or TI. Boulder refused to say what it is exactly, except that it is the same section found in the 866. Obviously, I could have removed the ten hex bolts from the top panel, cracked the 812 open, and looked, but that would have been rude. So, as of now it’s Boulder’s secret, but we can still make wild guesses.

The 812 employs balanced analog Class AB circuitry throughout, using op-amps to achieve a maximum of 19.4 volts of gain and a maximum output level through its balanced XLR outputs of 14 volts. Volume control is handled by an optically encoded 100-step control with 1.0dB increments. At 14 pounds, even the bulkiest cables would be hard pressed to pull it off a table.

Ergonomics

Since the Boulder 812 combines all the electronic functionality of multiple components into one svelte package, the controls and menus are complex. The owner’s manual is a must-read to discover all the features and options available. Boulder also developed an app to control all the 812’s functions for both iOS and Android platforms. It will find any Boulder components in your system and allow you to control them from your phone or tablet. Boulder also supplies a RF-based remote control for the 812, but I found that I used the app far more than the remote.

Input options for the 812 include Ethernet, one coaxial digital, two optical digital, one USB-B, two analog balanced XLR inputs, and four USB host connections. Output options include one pair of analog balanced XLRs on the rear, one 4-pin XLR, one ¹⁄⁸” single-ended, and one ¼” single-ended headphone on the front panel, which can be hidden behind a supplied etched-metal cover.

The 812 can function as a Roon endpoint, which is how I used it during most of the review period. The Roon controller apps on my iPhone, Android Fire pad, and Mac Studio all found the 812 with no issues. I also experienced no dropouts, stuttering, or slow loading of files. In short, Roon proved to be extremely stable with the 812 as an endpoint. You can also connect USB hard drives with additional music files to the 812, but they must have their own power supplies, as the 812 does not support power through the USB host connections. Since I have all my music files on a NAS drive, I did not try attaching a USB drive to the 812. Also, I found that most of my portable drives that are filled with music (such as the superb sampler from Wilson Audio’s Peter McGrath) were not self-powered.

As a headphone amplifier placed within arm’s reach the Boulder 812 was a pleasure. Festooned with four different connection points for either 1/8″ mini-stereo or 4-pin Pentaconn terminations, the 812 easily handled everything from 115dB-sensitive CIEMs to my least-sensitive headphones, including the Dan Clark Stealth, Abyss Diana, and Beyer Dynamic DT990 600-ohm model. Even though the headphone connections are all in a recessed rectangular space, there’s ample room for even the most oversized headphone-jack barrels. The 812 can power all four headphone outputs simultaneously, but unless you have four headphones with similar impedance and sensitivities you will probably find that some will be much louder or softer than others if all are connected at once.

The 812 includes one feature I’ve rarely seen on a headphone amplifier—a headphone connections cover. The reason given for this accessory’s inclusion is to keep dust out of the headphone connections. I suppose if you plan to use the 812 in a dusty environment, the cover would be an excellent idea, but in my time as an audiophile I’ve never personally experienced a headphone connection becoming intermittent or ceasing to work due to dust. But then I don’t have any systems set up in a woodworking shop, so I suppose in the right environment dust might be an issue. The cover is beautifully engraved and fits perfectly, but I would have preferred no cover so Boulder could relegate those cost savings to adding a second pair of analog outputs. You may feel differently, especially if you live in a desert.

Sound

Yep, sounds like a Boulder. I know that’s perhaps a bit too glib, but I have during my audiophile lifetime heard, owned, and reviewed quite a few Boulder Amplifier components. My history with Boulder goes back to its first consumer-audio gear. I owned Boulder AE500 monoblocks (driving the original Apogee Fullrange loudspeakers) and the Boulder LA5 preamplifier, heard many of its 1000 Series offerings at shows and in listening rooms, and recently finished spending time with the Boulder 866 integrated amplifier, so I think I’m as familiar with the Boulder sonic signature as anyone. That signature is all about transparency, neutrality, and not editorializing on the sonics in any way.

The Boulder 812 imbues every track with a special sense of solidity and cohesive energy. Also, the 812 has a superb level of lucidity, so that each recording retains its own particular soundstage and environmental characteristics. Some systems, especially those with big speakers in large rooms, often have only a one-dimensional soundstage presentation—big. The 812 doesn’t impose itself onto a recording. In my room through the Spatial X-2 loudspeakers driven by either a Pass 150.8 or Orchard Audio Starkrimson Ultra 2.0, monophonic recordings were seemingly no wider than a quarter, while big orchestral pieces, especially those made with three spaced omni microphones, were as spacious as the Grand Canyon.

After a period of time, to ensure that the 812 was performing optimally (some folks might call this burn-in), I attempted some matched-level A/B comparison with my current reference DAC, the Goldnote DS-10+. Using Roon, I can group any of the supported endpoints so that they receive the identical signal at the same time. This simplifies an A/B test. I say I “attempted” because ensuring an exact match of volume levels was impossible, since the 812 does not provide a volume read-out in dBs. The only indication of volume levels when using the 812’s volume control is a vertical row of LED lights. However, when using Roon or the Boulder app in variable-output mode, those apps provide a numerical volume display.

In DAC mode the 812 produces 3.95 volts from its balanced outputs according to its specifications. For my tests I tried using both the Goldnote and the Boulder in DAC mode, but the volume levels when receiving the same track via Roon’s grouped mode were not identical in level, so I switched the Goldnote into preamplifier mode so I could adjust its levels. I chose to control the Goldnote instead of the Boulder because the Goldnote has 0.5dB increments of adjustment, while the Boulder uses 1dB. But for critical matching even 0.5dB is not a fine enough increment for listening comparisons, though I got the levels close enough for WAGs (wild-ass guesses).

After much long-term listening and several semi-sighted A/B sessions, I could not reliably tell the difference between the Boulder 812 in DAC mode and the Goldnote DS10+. I say semi-sighted because, using the Schiit Freya S as my source selector, I did not know which DAC section was which, unless I looked at the little LEDs on the Freya that indicate which input had been selected. Since the Freya S is about eight feet from my listening spot, I couldn’t tell which input was selected until I got up and looked. Through both DACs my own live recordings of the Boulder Philharmonic at Macky Auditorium and those I made at the Salina Schoolhouse sounded exactly as they should have. Depth cues and imaging were identical as was the rhythmic drive and dynamic contrast.

I will add this caveat—I’m 72. My upper hearing limit at last test was 13kHz. If there are sonic differences above that frequency, I wouldn’t know. But while my hearing’s frequency range might not be what it was when I was in my 20s, my knowledge of sonic tells and access to high-quality reference material (including my own recordings) is far greater. So, if you’re an old wily audiophile like me, you may very likely arrive at the same sonic conclusions.

Summary

Judged solely on its sonic merits, the Boulder 812 delivers everything you could want from a high-performance audio component. Its limiting factors are ergonomic. For some potential owners the absence of a display that renders the volume in dBs may be an issue. For others the dearth of analog outputs might be a problem. But if you are looking for a superb-sounding platform for a small room, desktop, or nearfield system, the Boulder 812 could be a perfect fit.  

Specs & Pricing

Type: DAC, streaming endpoint, preamplifier, and headphone amplifier
Analog inputs: Two balanced XLR inputs
Digital inputs: Two optical, one coax, one USB, four USB Host, Ethernet, Wi-Fi, Bluetooth, AirPlay
Drive capacity: Four external self-powered USB drives
Formats supported: PCM to 256, DSD to 512, MQA, FLAC, AIFF, MP3
Outputs: One balanced XLR output
Headphone outputs: Balanced four-pin XLR, 1/8″ single-ended connector, ¼” single-ended connector, and Pentaconn
Dimensions: 12″ x 3.5″ x 12″
Weight: 14 lbs.
Price: $9250

boulderamp.com