Product Review - Bel Canto Design eVo 200.6 Multi-Channel Digital Power Amplifier - Part 2 - April, 2002
John Kotches, Editor PC/Home Theater
What makes this thing tick?
Without getting into the sonic merits yet, there are a number of advantages to digital amplifiers. First is very high efficiency. Most run > 85% efficient (for every 100 watts drawn from the wall, 85 are available for output). The eVo performs quite well here, with over 90% efficiency. The positive side effect is for the number of channels, the weight is quite light. In this case, 54 pounds nets you six channels with 120 watts into an 8 ohm load, or 200 watts into a 4 ohm load. Further, with the high efficiency comes little waste heat - thermodynamics dictates that any wattage drawn from the wall not output into the speakers (or other parasitic drains in the chain) has to be radiated away as heat. Indeed, even during "reference level" marathons, the case barely got above room temperature and was always comfortable to the touch. If I didn't know better, I'd swear a cooling fan was installed (pictures above show that they aren't!)
The Tripath amplifier module is what really makes the eVo go. The Tripath module is a variable switching rate Pulse Width Modulation (PWM) amplifier, with pulse frequency ranging from 200 kHz to 1.5 MHz onto which some dither as added, and a single inductor/capacitor (L/C) pair acts as a low pass filter prior to output. The role of the L/C pair is to smooth the output waveform into a more "analog-like" waveform. Digital cognoscenti should note the similarity in components to the output filter of a DSD DAC found on SACD players.
There is argument in some circles over whether an amplifier is truly digital if it cannot take a digital input. There is no question that the modulation of the output transistors is binary, but whether you choose to call it digital is a personal prerogative. I've heard the arguments both ways.
The Sound of Digital amplification . . .
Unlike the previous digital amplifier in for review, the eVo showed no hesitancy to drive all the speakers I had at my disposal. This included my reference speakers as well as the Home Theater Directs reviewed earlier this year. If you look at the Sharp review, you'll notice I thought the performance with the Home Theater Direct speakers was a bit lacking, but the eVo showed no such difficulty. It drove them to quite good effect, and merely reinforced my positive conclusions. Of course, the Bel Canto is a much more powerful amplifier too.
My reference speaker setup is another item altogether, and I've been fortunate enough to have some very high quality amplification for them - my personal reference amp is the Cinepro 3K6, series 3 which is no slouch of an amplifier, as well as the BAT VK-6200.
The eVo gave away (literally) nothing to these fine amplifiers, save for absolute power output. I was fortunate enough to work with a pair of eVo 200.6s, starting with 5 channels at 120, with one unused, and completing with a bridged pair utilized to drive all 5 speakers, plus my passive subwoofer.
If your goal is reference level playback, and you're using the eVo 200.6, you will need to focus on speakers with sensitivity in the 90 dB range or higher for 8 ohm loads, and 88 dB or higher for 4 ohm loads. If you don't make it to that level, you will find the power output lacking a little. Even at the top of the amplifier's power output potential, you will hear no sense of strain, or change in characteristic tonal delivery. If your speakers are lower than these sensitivities, you should consider bridged channel configurations.
With each recording, I was rewarded with a crystal clear viewpoint into the music, from a variety of sources - Redbook CD, DVD-Audio and SACD. I think the recording that best depicts this amplifier's performance is the SACD of the Bob Mintzer Big Band "Homage to Count Basie". This is a DMP disc where the band is presented on the front of the soundstage, and surrounds are utilized in what I will call "ambience mode". Tom Jung utilizes the surrounds to give an uncanny reproduction of the space acoustic - and when everything is grooving along just so (One O'Clock Jump), I can't help keeping time on the ride cymbal with my right arm. Scott Robinson takes an extended tenor solo on this cut, paying his own homage to the past tenor giants to grace the lead tenor chair. Greats like Lester Young and Frank Foster are saluted in turn.
Then there's the new recording on AIX Records, John McCuen and Jimmy Ibbotson's "Nitty Gritty Surround". The surround mix on this disc is what Mark Waldrep calls the "stage mix" and what I call immersive. Whichever way you label the recording, the goal is to enfold you within the band, and the recording was done live with the musicians in a circle configuration. I'm never disappointed with the sonic quality that Dr. Waldrep captures, and it's tough to pick one or two favorite cuts from a disc of gems. It's Morning is featured on AIX' sampler disc, but I'm also partial to Swing to Bop. Unlike some other recordings, there is a total lack of harshness and a purity of tone which makes me wonder what Mark knows about recording that many others don't. The acoustic instruments all get there own space within the soundfield, and the vocals are so well done, that you want to dig up other material as it becomes available from this small but growing record label.
I would be remiss not to discuss the stereo performance of two channels for this amplifier, and I'm going to resort to a "guilty pleasure" disc Kenny Loggins' "Greatest Hits" SACD. In Kenny's duet with Stevie Nicks Whenever I Call You Friend, you're greeted with an enormously large soundstage, spreading well beyond the loudspeakers and an analog to DSD recording path which makes this a nice "guilty pleasure" if you can handle the production qualities. It's loads of fun to hear the opening a capella choir expanding out of the speakers to make your room grow as you listen. The improvement over my reference amplifier is noticeable, but not night and day either. Since this is subjective, I couldn't begin to tell you
DTS / DD and Redbook CD certainly had their fair share of playback time, but the experience paled in comparison to the performance of the available high resolution formats. Once you get hooked on DVD-Audio and SACD, it becomes difficult to listen to lower resolution formats. The eVo was effective in delivering the weight, the subtleties and the emotional context as you are drawn into the world of the composer's design.
That's it . . .
This is the part where I present my conclusions about the amplifier. The eVo 200.6 is a "bargain" if this can be said about an amplifier that's only a few percentage points away from US$5000. It is quiet, clear, and as accurate as I can determine, and while the power output doesn't put it into the "gargantuan" category, bridging channels nets you substantial power increases (albeit at the cost of doubling your amplifier purchase). Even in bridged mode and at roughly US$10,000 for a pair of 200.6s it is competitive with conventional high-performance analog amplifiers at similar prices.
Good digital amplifiers are in their infancy, and the Bel Canto Design's eVo is a very precocious child - I was informed in no uncertain terms that my last amplifier purchase was in all likelihood the last analog amplifier I will buy. The Bel Canto amplifier, though relatively modest in terms of power output without bridging, is a powerhouse sonically.
Pick a channel configuration (monoblock, stereo, multi-channel) and pick the eVo to match. You'll be rewarded with great sound any direction you go. Other digital amplifiers are on the way, and I am very excited about getting some of them here to listen to. Sometimes it's tough to be a reviewer!
The eVo 200.2, 200.4, 200.6 have been replaced with the eVo2, eVo4 and eVo6 respectively. Other than cosmetics, the eVo4 and eVo6 are identical to their predecessors. The eVo2 includes the larger transformer used in the multi-channel amps as well as doubled capacitance over the 200.2.
- John Kotches -
© Copyright 2002 Secrets of Home Theater & High Fidelity
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