Integrated Amp Reviews

What's the first thing that comes to mind when you hear the word "boulder"? I think of a rugged, mountainous landscape with jagged snow-capped peaks. I see images of the last time I drove up from sunny Boulder, Colorado, to Rocky Mountain National Park and discovered so much snow coming down that if we had dared walk too far in, our trail would have been covered with snow and we'd never have been able to find our way out. But how magical it was!

My first visit to the area was in late July 1972. I was fleeing New York City for the Bay Area in an old car that burned oil. The park provided welcome relief from the long, monotonous drive. The Summer of Love was long passed, but when we stopped high in the park and ran through wildflower-covered mountainsides, I felt like the flower child I never was. Today I view that escapade with regret—in our innocence, we were unaware that our carefree frolic was doing lasting damage to a fragile landscape—but I'll never forget the joy that flower-covered mountainside brought.

I want my audio components to grant me experiences as varied, risky, and ecstatic as those I've had around Boulder. I want the high end to transport me to Strauss's climactic peaks and into the heart of Schubert's winter despair. When I listen, I want to feel as cool and sophisticated as Patricia Barber and as joyous as a choirboy singing of sleigh rides through the snow.

That's a tall order. Can Boulder Amplifiers' new 866 integrated amplifier ($13,450, or $14,950 with optional upsampling Roon-ready streaming DAC)—which co-designer Jameson Ludlam told me was "a more accessible product that provides the features we think many people are looking for with the performance they have come to expect from Boulder"—reach the summit?

The terrain
The Boulder 866 integrated amplifier's chassis somewhat resembles an accordion, with an angled front panel and irregularly shaped, oddly angled, smooth-edged heatsink fins. Dominating the view is a large color display that's easily read from 12' away. Four large buttons (volume up and down, mute, standby/on) are lined up on the right under the engraved nameplate. The 866 looks unique, sophisticated, and accessible.

Rear connections include three pairs of XLR analog inputs and two pairs of Boulder's signature, easy-to-tighten binding posts. The 866 comes in two versions: "all-analog" and "analog+digital." The "analog+digital" version adds AES/EBU, Ethernet (RJ-45), and TosLink digital inputs and four USB-A receptacles, the kind of USB used to connect a USB storage device (footnote 1); you cannot connect a computer by USB. "It is our opinion that Ethernet or network playback is preferred to USB playback. Ethernet is incredibly fast. It is difficult to get full high resolution through USB, and Ethernet doesn't have those kinds of problems [because it] is not distance-limited the way USB is."

What's inside? It's a secret—not. "We're kind of a bit of a hush-hush company," Ludlam explained during our call. "We don't like telling people too much about how we do things." He then proceeded to say quite a bit.

"What matters on the technical front is what choices you make as a designer and what compromises you carefully consider."

Ludlam worked with Boulder founder, company head, and analog specialist Jeff Nelson, laying out the circuit boards and overseeing how the product was assembled. "I didn't design the DAC software, but I did design how the data enters and exits the DAC and how we go from digital to analog," Ludlam told me.

"This is a drastically different design than our old integrated. The 866 has digital inputs, a completely different interface, and performs at another level. Some of the biggest circuit-design differences are in the volume attenuators, how the gain stages work, and grounding topology. In designing the flagship 3050 mono amplifier, we used a grounding technique that exists in the RF world and that, as far as we know, no one in the audio world is doing. But it's made every product we've produced since the 3050 better.

"The biggest contributor to the Boulder sound is that we treat analog like analog. ... Our biggest amps have a differential output, which means that they drive both the plus and minus output of the speaker terminal. You might think of it as a kind of bridged amp that drives the speaker differentially. [Each amplifier in] the 800 series, by contrast, is like a regular amp where the minus terminal is zero volts all the time. Besides that, there's just more stuff in our bigger and more powerful amps. With the 866, we did try to simplify certain aspects. But the overall design mentality is the same. Our attenuator has very, very little noise. We don't use pots or variable resistors because they wear out and start to crackle. You get the same sound quality anywhere on the volume control—it just gets louder as you turn it up. There's no sweet spot in the volume control.

"In our top-level products, we hand match and calibrate components to extremely precise percentages, selecting a few parts out of thousands," Ludlam said. "Whatever doesn't make the cut can still be used in less critical circuits or the next levels down." There's less meticulous parts-matching in the 866, another cost-cutting measure.

From Roon, I learned that the 866 upsamples PCM files to 352.8kHz. Ludlam wouldn't say which DAC chip the 866 uses, but he did say it's a single differential DAC chip per channel and that it's not one that's commonly used in high-end audio. "It requires a lot more external support circuitry than the typical DAC chips that other audio companies usually employ.

"We have never been discouraged by complexity in circuit design, so we actually prefer to do as many of the circuits ourselves as possible rather than relying on more of an 'off the shelf' DAC topology. We use the DAC chip in an undocumented mode. As far as we know, no one else uses it like this. Rather than letting the DAC do the computing, we do our own math in DSP and then feed that data to the DAC chip. We always send the same kind of data to the DAC regardless of what file type you're using. That's the beauty of DSP. ... If we found a better DAC chip, we would use it, but we haven't found a better one that also supports playback of DSD 64 and 128."

I've spoken with many a company owner, designer, and rep over the years, but few have provided such an honest assessment of a product's strengths and limitations.

"Obviously, bigger amps give you more control of the woofer and a greater sense of scale. A speaker is really a motor. An amplifier puts voltage across the motor, the motor pushes a cone, and that cone pushes air at you. A bigger amp pushes the speaker the way it wants to; a smaller amp sometimes gets pushed around by the speaker. We have very high damping factors on all our products—we have lots and lots and lots of control—but you just get more with more.

"The big amps create a space, a separation between the background and what you're listening to. They move things more precisely, and everything stands out proud from the background. More power gets you a better sound if you know how to control it.

"Ultimately, what I'd say to people is that you need to listen to this integrated and see if it brings you happiness. That's the whole point: to experience happiness. I could wax on and on about technical matters, but just listen to it. Of course, the bigger stuff is better, but this still sounds really great and is reachable by far more music lovers. It is a fantastic-sounding amplifier."

Following Ludlam's advice, I'll be the judge, as I hope you will, too.

Preparing for the journey
To cut costs, Boulder put the 866's owner's manual online, including only an illustrated Quick Start Guide in the box. The documentation is thorough, with just one oversight: There's no mention of the fact that the diminutive "remote receiver" you must plug into one of the unit's USB ports to enable communication with the remote comes stashed in the remote's empty battery compartment (footnote 2). Presumably, Boulder will amend its literature to address this—and to offer pointers on how to open said battery compartment.

Although a digitally equipped 866 has its own wireless network, which you can use for file playback when a wired connection is not possible, Ludlam and sales coordinator Logan Rosencrans both urged me to hard-wire the 866 to my own network. Hence, I moved my Wireworld Ethernet cable over to the 866 and switched audio settings in Roon.

When asked whether a power conditioner should be used, some amplifier manufacturers urge caution. Boulder is one of a handful of companies to issue an unqualified "no." I've almost always found, though, that my AudioQuest Niagara 5000 improves bass control and impact, removes noise, and produces a more transparent and lifelike representation of music. I went back and forth between the wall and one of the Niagara 5000's high-current receptacles, comparing sound. My typical experience was confirmed one more time: I noted a bit more texture and detail on voice and instruments with the 5000, more saturated colors, a better-defined sense of space, and better bass. I mentioned this to Ludlam.

"I'm not here to dictate," he answered. "We say 'no power conditioners' because we tire of very long conversations where we argue about the merits of one over the other. It's much easier to say, 'No power conditioners.' But if it works, it works. My biggest concern is that there are some that have ground lifts and actually have a driven ground. Legally, those are not UL certified." (footnote 3)

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Footnote 1: USB sticks can be used by themselves, but hard drives require more power than the USB port can provide and so must be self-powered.

Footnote 2: I thought I'd lost it, which made me none too happy.

Footnote 3: When questioned about this, AQ power conditioner designer Garth Powell wrote, "All grounding of the Niagara 5000's high-current outlets (for power amplifiers) is chassis star-grounded and NRTL code–compliant. Our international units are CE compliant as well. ... I take electrical safety very seriously."