Bel Canto e1X power amplifier

I own and enjoy loudspeakers from seemingly opposite ends of the audiophile spectrum: I'm a huge fan of minimally efficient yet otherwise overachieving flat-panel designs, such as my Magnepan LRS speakers. Yet I'm just as smitten with another, equally outside-the-norm alternative: high-sensitivity full-range loudspeakers, such as my Zu Omens—especially when driven by tube electronics. It's an ongoing yin and yang that keeps my home system in a constant state of flux: Alternating between loudspeakers that use such different technologies, while maintaining relatively optimal positioning for each, is a bit daunting. But there's an even bigger challenge: finding a single amplifier design that's simpatico with both. While tubes would be the obvious choice for the Zu loudspeakers, all-tube amplifiers with sufficient power for my Maggies are definitely outside my fiscal comfort zone.

That's where Minneapolis-based Bel Canto Design comes into the picture. I've heard great things about their class-D solid-state amplifiers for some time, but they've always existed on the periphery for me: I considered Bel Canto amps a bit too esoteric for my relatively utilitarian system. But now's the time to rethink that perspective: With their new e1X product line—a stereo power amp, a preamp/DAC, and an integrated amp—Bel Canto suggests that they're making a generous portion of their top-line technology available at a significant cost savings. Hence this review of their new e1X Stereo Amplifier ($6000), which is priced 40% lower than its predecessor in the Bel Canto Black EX line.

Description
The e1X Stereo Amplifier is indeed a class-D design. Its rated output power is 250Wpc into 8 ohms and 500Wpc into 4 ohms, and e1X is reportedly stable into 2 ohms. The amp also has internal switches to select between 27dB and 33dB of overall gain, when needed to accommodate different loudspeaker sensitivities. The e1X's damping factor is specified as greater than 500, its dynamic range as 126dB. I asked John Stronczer, Bel Canto's founder, CEO, and chief of design, to expound on the class-D technology employed in the e1X, and he responded with the following: "The output stage is a low gain Ncore class-D stage that provides extremely low noise and distortion while delivering up to 30 amperes of current. The overall architecture of this amp (and the other Ncore based products in our line) is a two-stage architecture with no global feedback.

"The first stage delivers most of the gain, either 14dB or 20dB depending on an internal switch setting and operates in class-A mode in the e1X amp. The second stage is the Ncore modulator that delivers all of the current to the speaker load and has a gain of 4.5× or 13dB. The first stage amplifier is our proprietary discrete Single Stage High Current class-A amplifier and uses selected resistors and capacitors for best performance. The signal path from the input stage through the Ncore modulator stage is fully discrete. There's more than 50dB of loop gain throughout the audio band in both the input and the Ncore modulator stages. The result is a constant low-distortion signature throughout the audio band and none of the coloration that can occur when feedback is used without adequate bandwidth or loop gain in the amplifier stages."

Stronczer also noted that the 100kHz switching power supply employed in the e1X is one of the key reasons for the relatively low mass of the amplifier (see below). The power transformer only weighs about a pound, compared with the typical 20lb (or more) of conventional 50/60Hz transformers used in some class-AB and class-A amplifiers. He continued: "The 100kHz operating frequency . . . results in lower magnetic core loss (a smaller core) and much lower copper loss in the transformer. This also results in better supply regulation under loading, and better response to dynamic load changes. This supply also does not suffer from the typical 50/60Hz harmonic noise radiation that can color the midrange of many audio amplifiers. The resulting midrange clarity is proof of this approach." Stronczer also mentioned that class-D output stages don't suffer from the typical thermal wander effects that can color the sound of more conventional class-AB designs.

I also asked Stronczer how they managed to get the price down to $6000 vs the $10,000 price of its counterpart in the pricier Black EX line. He told me that while the internal circuitry of the e1X shares much of the Black EX amp's goodness, there were certain design constraints necessary to lower the price. Principally, the more expensive Black EX amplifier is a higher-powered design, rated at 700Wpc (4 ohms) vs the e1X's rated 500Wpc into the same load. And the Black EX amp is a true dual-mono design, with independent 1200W power supplies and signal paths for each channel. A higher grade of silver/gold wiring is employed in the EX series, and the chassis and case design uses machined aluminum plates and is substantially more robust. But John assured me that, despite significant differences between the two amps, the overall gestalt of Bel Canto's other amplifier offerings is definitely present in the e1X.

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Setup and installation
When the e1X arrived, I was immediately struck by how very light the shipping box was: The combined weight of amplifier and carton is only 18lb! In addition to being lightweight and relatively compact (17.75" wide × 15.75" deep × 3.25" high), the e1X has a spare, uncluttered rear panel, with connections as expected: single-ended (RCA) and balanced (XLR) inputs, stereo pairs of WBT Nextgen loudspeaker connectors, and an IEC socket for the AC cord. Michael McCormick, the Bel Canto's president, mentioned that the company has no specific recommendations with regard to power conditioning, in the absence of which my best bet would be to connect the amp directly to the wall. My listening room has dedicated AC outlets for audio equipment (10-gauge Romex, Hubbell outlets); I used a custom Rite Audio Cables High Current Sound Pipe AC cable to supply power to the e1X. The amp has a rear-panel main power switch, and there's also a standby switch on the front panel.

McCormick suggested that I first make all the necessary equipment connections, then allow the amplifier to warm up and burn in for a minimum of 72 hours before doing any critical listening. After unboxing, I took the e1X downstairs and swapped it in place of my Emotiva XPA-1L monoblocks—and in doing so, I noticed what might be perceived as a bit of a problem: The Bel Canto's casework is so incredibly lightweight that unwieldy, cumbersome cables, such as my MG Audio Planus II loudspeaker cables, actually pulled the e1X back and forth across the amp stand. (Note also that the speaker connectors for both channels are at the same end of the e1X's rear panel, apparently done to maintain short signal paths in this non-dual-mono design; that too made connections with bulky cables a little more difficult than the ideal.) Even my AudioQuest Yukon XLR interconnects had the amp sliding all over the place. I wondered if something even pointier (or gripper) than the e1X's conical footers might make it less prone to movement.

This e1X generated negligible heat and could surely be left powered on.

Listening with the Magnepan LRS
There's a cult following in the audio world for small Maggies such as the LRS ($650/pair), and I count myself among the faithful. Some of us feel that the only thing separating the LRS from Magnepan's more expensive offerings is careful amplifier matching—that and perhaps a few well-chosen tweaks. As for the latter, I upgraded my pair with a set of third-party custom stands from Magnarisers.com: They've made a tremendous difference in the performance level of the LRS.

COMPANY INFO
Bel Canto Design
221 1st St. North, Suite 300
Minneapolis, MN 55401
(612) 317-4550
ARTICLE CONTENTS

COMMENTS
Bogolu Haranath's picture

Mr.Tom Gibbs has good size listening room suitable for reviewing large size loudspeakers :-) ........

Bogolu Haranath's picture

Mr.TG could review the new, more powerful, same price as the Bel Canto, PS Audio Stellar M1200 mono-blocks, $6,000/pair ...... They are hybrid tube/Class-D design amps :-) .......

dial's picture

6000 $ to drive 650 & 2250 $ speakers is strange. Some years back, an old friend of mine had two Goldmund separates (purchased second hand) and a pair of Triangle Titus. So why not ?
And this amp has beautiful WBT NEXTGEN connectors.

Ortofan's picture

...Bryston 4B3. Slightly higher output power capability and a 20-year warranty, instead of only 5 years from Bel Canto.

Otherwise, the still more powerful Parasound Halo A 21+ costs only $3,000.

The yet again more powerful Rotel RC-1590 costs $3,500.

OTOH, if you need a fancy brand name to impress your fellow audiophiles, then the Mark Levinson No. 532H, with an output capability similar to that of the Bel Canto, is now available for $6K.

None of these amps requires an external filter to limit ultrasonic garbage at their output.

https://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1699:bhk-labs-measurements-bryston-4b3-stereo-mono-amplifier&catid=97:amplifier-measurements&Itemid=154

https://www.stereophile.com/content/parasound-halo-21-power-amplifier-measurements

https://www.bwgroup.ch/wp-content/uploads/2016/11/Hi-Fi-News-11-2015-Test-Rotel-RC-1590-RB-1590.pdf

https://www.stereophile.com/content/mark-levinson-no532h-power-amplifier-measurements

Bogolu Haranath's picture

Parasound JC-5 can put out more power and costs the same, $6,000 :-) .........

Bogolu Haranath's picture

However, if you are one of the 'green new deal' supporters, Bel Canto and PS Audio Stellar amps are good choices :-) ........

Kal Rubinson's picture

I will not argue any of your suggestions but I believe that more apt comparisons might be among amps that can be as easily lifted as the BC. :-)

Bogolu Haranath's picture

May be Ortofan's 'Total-T' levels are higher than many of us .......... Just kidding Ortofan :-) .......

Ortofan's picture

... been my first suggestion, except that Benchmark does not specify an output power rating for operation in bridged mono mode into a 4Ω load.

If spending $6K on a power amp, I'd try to scrape up another $1K and buy a McIntosh MC312. 385W into either 8Ω or 4Ω should be sufficient. If not, the power guard feature will prevent clipping. The dealer will deliver it and the amp need never again be moved until after I die. Plus, it has those blue lit meters.

Bogolu Haranath's picture

Recently reviewed Primare A35.2 Class-D amp is slightly less powerful, and costs $3,500 :-) .......

Bogolu Haranath's picture

Stereophile Class-A, PS Audio Stellar M-700 Class-D monos are more powerful and cost $3,000/pair :-) ........

John Atkinson's picture
Ortofan wrote:
None of these amps requires an external filter to limit ultrasonic garbage at their output.

Neither does the Bel Canto when used to drive a pair of loudspeakers. But as I have explained, I need to use such a filter when measuring class-D amplifiers to avoid driving my analyzer's input stage into slew-rate limiting and thus give inaccurate distortion readings.

John Atkinson
Technical Editor, Stereophile

jeffhenning's picture

You and your crazy fear of input stage slew-rate limiting. The next thing you are going to say is that your measurements are accurate and relate to the sound you can hear.

You nutty kid!

a.wayne's picture

Hello John ,

So whats causing the poor Squarewave responses ..?

Regards

John Atkinson's picture
a.wayne wrote:
So whats causing the poor Squarewave responses?

The Bel Canto's squarewave response isn't "poor." In the 10kHz squarewave (fig.2), the lengthened risetime is associated with the ultrasonic rolloff (-3dB at 38kHz) seen in fig.1. There is a very slight overshoot on the waveform's leading edges but this is not accompanied by any ringing.

John Atkinson
Technical Editor, Stereophile

dc_bruce's picture

It's probably worth noting that when Jim Whinney introduced his "Magneplanar" speakers in the early 1970s, he demoed them with a 60 watt Audio Research tube amp. I first heard the Magneplanar (a 3-panel speaker, IIRC) demonstrated in 1972. I believe the transistor amps of the time were rated at about the same power output and clipped pretty nastily, unlike the ARC tube amps. Supposedly, the Magneplanar was much easier load, not being particularly reactive like cone speakers. I think people's expectations about loudness was less than it is today, and the Magneplanar was very listenable, as it remains today.

dial's picture

I owned a pair of MG III A I had to sell to a good friend of mine due to WAF. Now the W is gone but the speakers still play fine in his listening room with a Goldmund studio Sumiko blue point special and pre + amp combination by Audioanalyse.

jeffhenning's picture

Thinking of the white papers and reviews of nCore amps I've seen in the past, they usually have a lot less distortion in the treble than this amp. In fact, they usually have very little rise in distortion as the frequency goes north.

That makes me wonder if this is a "feature" of Bel Canto's input stage.

Regardless, for around $1,800 or so, you can get Nord to make you an amp with one of Bruno's latest Purifi amp modules with a choice of input op-amps.

I think that says all you need to know on this subject.

David Harper's picture

While it is particularly important (with maggies)that an amp be a good match for them (I have the LRS speakers) it has nothing to do with the price of the amp. Rather it is about impedance,power output, current capability, etc. Correctly designed high-quality power amplifiers, when not overdriven, do not vary in sound quality.I'm driving my maggies with a Schiit Vidar amp which cost $700 and the sound quality (again, when not overdriven) is equal to that of any other amp regardless of price.

Bogolu Haranath's picture

In a recent review of Primare Class-D amp, HR used the Primare and Bel Canto Class-D amps to drive his Magnepan .7 speakers and got good results :-) ........

Tom Gibbs's picture

A couple of things; yes, $6000 is a lot for an amplifier to drive a $650 pair of loudspeakers, but it makes a couple of things really very clear. 1) When Wendell Diller says the Magneplanar LRS is built to show its mettle with higher-quality electronics, he's not overstating his position. The LRS will handle high input power levels and reproduce impressive dynamics with the Bel Canto e1X without flinching. 2) Sometimes it's possible to get a significant portion of a manufacturer's higher-end excellence at a very reasonable price point. The LRS is an almost unbelievable example of this, and also, though at a significantly higher price point, so is the e1X; it gives you so much more than just a taste of Bel Canto's top-line design implementations at a significantly reduced price.

Bogolu Haranath's picture

May be Mr.TG could review the new Yamaha NS-5000 speakers? :-) ........

dial's picture

Thanks for your answer, I'm not at all surprised, as I tell you all about the guy having Goldmund separates (Mimesis series), -they didn't produce anything integrated at the time- and cheap bookshelf Triangle speakers. He also owned a Goldmund studio with linear tonearm and Gold cartridge. I loved the sound of his speakers, despite the lack of deep bass, mostly absent from vinyl. And then he bought a California audio labs CD (Goldmund didn't produce CD players then) quickly changed for a Wadia. So perhaps it makes sense, following Ivor's audio philosophy...

Ali's picture

Class D, it seems, getting momentum!

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