Bob Barrett is a versatile writer and knowledgeable hi-fi enthusiast whose work for HomeTheaterReivew.com runs the gamut from mid- to high-end home theater to audiophile components and speakers. He also specializes in high-performance and high-end headphones.
"Good things come in small packages." While that idiom may hold true for some things, it certainly hasn't been the conventional wisdom among audiophiles when considering the quality of amplifiers. The bigger and heavier the amp, the better, right? If lifting an amplifier doesn't cause your lower back to cry out, it can't be any good, can it?
Enter today's digital amplifier technology. For the past 10 years, Red Dragon Audio has been designing, building, and marketing digital amplifiers at realistic prices to audio and home theater enthusiasts in the U.S. and abroad, all from Salt Lake City, Utah. Until the opportunity came up to review the new Red Dragon Audio S500 stereo amplifier ($1,999), I hadn't actually listened to any of the company's products.
Sure, I had heard of Red Dragon and had even walked by its demo room at a couple of audio shows, but I never took the opportunity to stop in for a listen. There are always more products than time at a show. However, opportunity was on my side at T.H.E. SHOW Newport earlier this year, where Red Dragon was demoing the new S500 stereo amplifier. I made a point to stop by this time and get an audition. That brief listen piqued my interest. I liked what I heard (or rather, what I didn't) and looked forward to a more lengthy evaluation of the S500 in my own system. While talking with Ryan Tew, engineer and founder of Red Dragon Audio, about shipment details of a review sample, he asked if I might want two S500 amplifiers so that I could also audition them in BTL (bridge-tied load) bridged mono mode. I said yes and was shipped two units shortly thereafter.
Red Dragon utilizes a stock Pascal S-Pro2 amplifier module but adds a proprietary input buffer stage. Pascal A/S (Ltd.) may be unfamiliar to many audio enthusiasts. The company is headquartered in Copenhagen and best known for producing OEM amplifier modules for the Pro PA loudspeaker industry. While using a stock amplifier module helps Red Dragon to keep costs reasonable, this particular amplifier module has some unique features and was specifically designed for the audiophile market. Taking Class D technology a step beyond the more common ICEpower modules originally developed by B&O and found in many current digital amplifier designs, the S-Pro2 amplifier module incorporates Pascal's patented UMAC Class D technology. The S-Pro2 is said to be the world's only Class D amplifier without an HF (high frequency) damping network. This means it provides full power bandwidth to 20 kHz. As mentioned earlier, the S-Pro2 can be operated in either stereo mode or BTL bridged mono mode. That's a pretty unique feature for a digital amplifier at this price point. The S500 amplifier is rated at 2 x 250 watts at eight ohms (2 x 500 watts at four ohms) in single-ended mode or 1 x 1,000 watts at eight/four ohms in bridged mono mode. The S500 also has a maximum current output of 30 amps. This means that the S500 has a lot of power headroom and should be able to drive even difficult loudspeaker loads.
All of this power is packed into a 12-pound aluminum chassis with a form factor of just 16 inches by 7 inches by 3 inches. The minimalist industrial design of the S500 is available in either a brushed silver or anodized black finish, the latter being the finish of the review samples sent to me. Both the company name and dragon logo are engraved on the thick aluminum front panel, and the logo glows red when the unit is powered on.
While the increasing number of channels found in AV receivers in recent years has made the inclusion of digital amplifiers a practical necessity, the acceptance of their use in both mono and stereo designs has been slower to gain acceptance among the traditional audiophile community. These days however, there are several examples of digital amplifier products from respected high-end companies including Jeff Rowland, Gato Audio, and Classé. How do they sound? As Jerry Del Colliano so aptly pointed out in his recent review of the Classé Sigma AMP5 Class D five-channel amplifier, the old cliches that Class D amps sound clinical, lifeless and lack real bass aren't necessarily true anymore. Does that hold true for the Red Dragon S500 amp, as well? Well, that's what I intended to find out.
The back panel of the S500 is clearly labeled, making hookup a straightforward task. I first integrated a single S500 amplifier into my reference system using Wireworld Silver Eclipse 7 balanced interconnects and speaker cables to connect the amp to my reference Classé preamp and Aerial Acoustics floorstanding speakers. Connecting the speaker cable spade terminations to the amp's binding posts was an exercise in patience, given the tight space between connections and the stiffness of the speaker cables. Either having a little more real estate between connectors or banana terminations instead of spades would have made the job much easier. I also connected the 12-volt DC trigger output of my preamp to the trigger input of the S500 with the included cable to enable remote power on/off of the amplifier.
A couple of other adjustments were necessary before powering up the amp. There is a switch on the right side of the back panel to select between the RCA and XLR inputs. There is also a push-button switch on the back panel's left side to select between stereo and mono operation. This push button is recessed to prevent accidental engagement.
Over a two-month period, I listened to a wide variety of source material with a single S500 in stereo mode. Then I added the second S500 amplifier into the system, resetting the operation of the amps to bridged mono mode. Again, I listened to a lot of the same source material for another couple of months, but this time with a dedicated amp for each channel, effectively doubling the power output to each four-ohm Aerial Acoustic loudspeaker to a staggering 1,000 watts.
Over the several months that the Red Dragon S500 amplifiers were in my system, I listened repeatedly to several very familiar tracks with both a single S500 amp in stereo service and two S500 amps playing in bridged mono mode. My listening notes were consistently similar for a given piece of music in either mode. The only difference between the two was a matter of degrees. When the two bridged mono S500 amps were in play, sonic traits were turned up a few notches--and this was the case even though I carefully volume matched the two amplifier configurations. For example, in bridged mono mode, soundstages were typically just a bit wider and deeper, instruments were slightly more precise within that soundstage, and bass dynamics and impact were enhanced a notch.
To test the ability of the Red Dragon S500 to convey low bass impact, I used Tidal HiFi to stream the track "The Hills" on the Beauty Behind the Madness CD (XO & Republic Records) by The Weeknd (a.k.a. Abel Tesfaye). This track has a low droning electronic bass beat that serves as the perfect backdrop for the dark and graphic imagery of the song's lyrics. This is juxtaposed by a delicate section after the second chorus that really shows off the singer's signature falsetto as it rises higher and higher. The bass in this track can sound a bit muddy and anemic with lesser amplifiers, but the unassuming Red Dragons proved their mettle with more than enough power in reserve to portray the challenging bass beat with the same impact and accuracy as my reference Classé amplifier, all without even breaking a sweat. I felt that same visceral vibrating in my chest from the bass as I experienced with this track played through my Classé amp.
To evaluate the Red Dragon's ability to deliver dynamics and precise soundstaging, I used a couple of tracks, the first being "Amused to Death" (Analogue Productions) by Roger Waters on the SACD of the same name. The Red Dragon amps in stereo mode (and even more so in mono mode) have more than enough reserve power to accurately portray the staggering dynamics of this recording, and the extremely low noise floor of the S500 really became evident during the quietest passages, providing an almost eerie blackness. The low bass also came through with depth and clarity during the middle parts of the track, with the Red Dragons providing more than enough power to project a rock-solid bass foundation during those passages. The soundstage width and depth were only limited by the boundaries of the front wall and two side walls. The television voices in the background seemed to come at my listening chair from the sides. You might expect this from the 5.1 mix, but I was listening to the stereo mix. Plus, there were sounds that seemed to emanate from the surface of the front wall itself, five feet behind the speaker drivers. The visual portrayed by the extreme soundstage width and depth was similar to the experience of watching a 3D movie in an IMAX theater.
Another memorable track for soundstaging and low bass definition was "The Pressure" by Jhené Aiko on her CD Souled Out (Def Jam Recordings). The S500's substantial power reserves contributed to the feeling that the room was shaking a bit with every strike of the kick drum. The recording was made using Jhené's voice for background vocals, as well as the lead vocal. The background vocals appear as multiple echoes that seem to bounce off the side walls and even from above the listening position, as though Jhené were singing in a canyon. The soundstage width created by the S500 amps in mono mode was a bit wider than a single S500 in stereo mode or with my Classé amp. The way the music wrapped around me, it actually sounded more like a surround recording than a two-channel recording.
While the Waters and Aiko tracks were recorded to project a very wide soundstage, the degree to which this was actually teased out of the recording and accurately reproduced is in no small part influenced by the characteristics and quality of the amplifier in play. And in this regard, the Red Dragon S500 more than met the challenge.
Another track of note was "Tin Pan Alley (a.k.a. Roughest Place in Town)" from the SACD Couldn't Stand the Weather (Mobile Fidelity Sound Lab) by Stevie Ray Vaughan & Double Trouble. The power reserves of the S500 put real authority into the pluck of Vaughan's electric guitar. Every instrument was distinctly placed within the soundstage, and there was a sense of air around each instrument. The buildup and decay of notes played on the rhythm and bass guitars created the palpable ambience of a live performance. I felt instantly transported back to Buddy Guy's Legends in Chicago, an oasis for live blues music that I've been fortunate enough to experience on several occasions.
No product is perfect, but I only encountered one issue with the Red Dragon S500 amplifier--namely, the tight clearances and orientation between the speaker cable binding posts, single-ended, and balanced connections all made the speaker cable connections in stereo mode quite challenging. Squeezing the right speaker cable's positive termination and the left speaker cable's negative termination between the balanced and unbalanced connectors took a lot of patience to get a solid connection. In the end, I also had to place the back panel of the S500 at the back edge of my audio rack, allowing the speaker cables to hang down because of their inability to bend sharply enough. Alternatively, placing the amplifier onto an amp stand would provide additional clearance height for larger-diameter speaker cables. Connections were quite a bit easier when the amps were configured in bridged mono mode, only having to fit spades to the two outer binding posts.
Comparison and Competition
The Red Dragon S500 stereo amplifier competes against products like the Bel Canto e.One REF500S stereo amplifier. Listing for a bit more at $2,595, the Bel Canto has a slightly more upscale appearance, if aesthetics matter to you. Incorporating a proprietary amp module design, it has similar specs to the Red Dragon but lacks the ability to operate in BTL bridged mode. The CI Audio E?200S stereo amplifier delivers a little less power, with a rating of 200/400 wpc into eight/four ohms, respectively, but also costs a bit more at $2,500. Like the Bel Canto, it also lacks the ability to operate in bridged mono mode. If that's not an important feature for you, I suggest auditioning these amplifiers along with the Red Dragon. If the option of operating in bridged mono mode is an important feature, the choice at this price range is a straightforward one.
The Red Dragon S500 stereo amplifier is not only a serious contender at its price point, it can hold its own against amplifiers costing considerably more. If you have loudspeakers that are somewhat difficult to drive but you don't want to hassle with the size, weight, and heat output of a traditional Class AB design, I recommend you audition the Red Dragon Audio S500 digital amplifier. Or, if you want to set up an audiophile-grade home theater with lots of power in reserve at a reasonable price, consider a set of these Red Dragon amplifiers mated to a quality preamp/processor. With Red Dragon Audio's 45-day money-back guarantee, what have you got to lose? The S500 amp might just rock your world when it comes to the way you think about amplifier design versus performance. When it comes to the Red Dragon S500, good things do indeed come in small packages!