When assembling a two-channel audio system, I've always gravitated toward an integrated amplifier. I like the idea of a one-box solution -- it takes up less space and sacrifices only a little performance compared to a separate preamp and power amp. With only one power supply, all other things being equal, an integrated amp tends to be more power efficient. Integrated amps are way less fussy, too -- there's no worrying about preamp A matching power amp B or wondering which cable to use between them. I'll let the manufacturers put it all together so I can just think about what music to play.
Adding a DAC
The latest exciting trend is the proliferation of integrated amps with additional components, such as digital-to-analog converters. We're not talking mass-market $500 pieces here -- high-end manufacturers are getting in on the act. One of the first was Bryston with its B100-DA SST ($4545 including DAC), reviewed on SoundStage! in August of 2006. I experienced this component a couple of years back in one of the most effective demos I've heard in an audio store. Before this demo, I wasn't convinced that a DAC separate from what you get in a CD player would improve sound quality much. But when switching from the analog outputs of a high-quality CD player to the DAC in the Bryston integrated amp, I was startled -- I heard a larger, more detailed soundstage and airier highs. From that day forward, I got it.
Further refining the concept of a built-in DAC is the Esoteric AI-10 ($4400). This 110Wpc integrated adds an internally generated sync clock that connects to Esoteric's CD players. Syncing word clocks between player and DAC reduces timing errors, called jitter, resulting in better sound quality. Because it's a digital amp, it converts all analog signals to digital at up to 192kHz. While some may wonder if this impacts the sound, according to reviewer Philip Beaudette in his May 2010 SoundStage! review, this wasn’t the case at all.
Adding to a DAC
With the proliferation of Apple's iPod, the need to connect it or its files to an audio system is a necessity -- life or death for an equipment manufacturer that hopes to sell its wares to a new generation of music lovers. Apple didn't need to issue bumper stickers that read "Support the iPod or Die" -- consumers simply demanded it. Like it or not, the iPod has changed the way most of us listen to and store music. It has led not only to MP3 downloads, which can sound surprisingly good, but also to high-resolution 24-bit/96kHz downloads, which sound extremely good. Many journalists have predicted the end of disc-based audio and video storage. So what's new in the world of DACs? The addition of a USB port is certainly new, and it's now almost commonplace. Most of these USB ports don't support the iPod directly, but they will support any computer-based audio storage, like your iTunes Library.
The latest integrated amps with built-in DACs have added USB ports, too. Check out the Simaudio Moon i3.3 integrated amp ($3699 with DAC) reviewed in GoodSound! in June of 2009. In addition to the USB port, the i3.3 sports two coaxial and one optical digital connections on the back. This 100Wpc unit (which is rated to double its power to 200Wpc into 4 ohms) also has a 1/8" stereo jack in front to connect any MP3 player. Surprisingly, the Bel Canto e.One S300iU 24/96 ($1995), reviewed on SoundStage! in January, eschews S/PDIF inputs altogether and has a single USB input for connecting to your computer. Unlike the Simaudio Moon i3.3, the Bel Canto is a digital-switching amp in a remarkably tiny chassis, yet it's rated for 150Wpc into 8 ohms and a staggering 300Wpc into 4 ohms.
Being a devoted home-theater enthusiast, my world revolves around a receiver, projector, Blu-ray player, seven speakers, and a subwoofer. Putting all that together can require deep pockets, and for economical reasons, I’ve based my home theater on a receiver rather than separates. It’s a good one, but with a receiver everything is compacted to fit into one box. The amps aren't typically as good as standalone ones, the video section can add noise, and the preamp section won’t be as good as a competent separate preamplifier. With all the satisfaction I get from watching movies in 7.1 glorious channels, I still miss the sound quality and simplicity of two-channel audio.
When looking to add an integrated amplifier to my system, I always look for a home-theater bypass. By hooking up your main left and right speakers to the integrated amp, the home-theater bypass lets you disable the preamp section and use the power amp when watching movies. You can then reengage the preamp section when listening to two-channel music, so you get the best of both worlds. How simple is that? Some might say that all you need is to hook up the left/right audio outputs from your receiver to any integrated amplifier's Preamp In jacks, which almost all integrated amps have. I've gone that route, and it sucks -- you effectively have two volume knobs active, and you'd have to mark or remember where the volume of the integrated should be when switching back to your receiver. Bottom line: I wouldn't add an integrated amp to my system without the home-theater bypass!
Fortunately, there's no shortage of integrated amps with home-theater bypass switches that also incorporate built-in DACs. The previously discussed Bryston and Bel Canto have included this feature. As well, have a look at two SoundStage! Network Reviewers' Choice winners: the April Music Stello Ai500 ($3495) reviewed on SoundStage! in January of this year, and the Peachtree Audio Nova ($1195) just reviewed on SoundStage! in February.
The April Music Stello Ai500 features an amp section rated at 150Wpc into 8 ohms amp, doubling its power to 300Wpc into 4 ohms. A unique feature of this integrated amp is an iPod USB control port along with analog left and right inputs. Although the audio output will be analog, the Stello Ai500 remote control will navigate your iPod.
Perhaps the most exciting piece for me in this roundup is the Signal Path International Peachtree Audio Nova. This integrated amp is rated for 80Wpc into 6 ohms. It features a hybrid tube / solid-state preamp, so it can smooth-out the sound of harsh-sounding sources, speakers, or recordings. Is the sound too syrupy smooth? Signal Path has provided a button labeled Tube on the remote control -- press it and the Nova will bypass the tube section. Cool! Another aspect of this unit is the tube headphone section for high-quality private listening. If that isn't enough, the DAC section incorporates an ESS Sabre DAC. This DAC features a selectable switch for adjusting the filter slope from sharp to soft, allowing you to adjust the sound to your liking. This is the Burger King of integrated amps, as it lets you tailor the sound to Have it Your Way.
The kitchen sink
The final integrated amp that I'd like to bring to your attention is the NaimUniti ($3750), reviewed this month right here on SoundStage! Xperience. I don't know if integrated captures it all, because this piece is crammed with everything. Technically, it's a receiver because it has a built-in FM tuner. The power amp section is rated for 50Wpc into 8 ohms and 90Wpc into 4 ohms. The DAC section has five digital inputs and a front-mounted USB input. It will offer iPod control with an optional Naim n-Link iPod dock ($150). The NaimUniti's unique feature is the network connectivity, using either a hardwired Ethernet connection or a wireless-G connection. This opens up a host of cool features such as wirelessly streaming computer-based audio files and Internet radio, the latter allowing access to music content from around the world. If that isn't enough, Naim threw in a CD player, too. Note that all of these components haven't been slapped into a box haphazardly, but are based on Naim's highly acclaimed separates, so quality sound should be assured.
As you can see, the integrated amplifier has evolved into a sophisticated piece of equipment, adding such components as built-in DACs and wireless streaming and offered at a variety of prices. With high-end companies getting involved, the sound quality will be first-rate, too. These new integrated amps offer unmatched versatility, and I think you'll find the prospect of adding one to your system as exciting as I have.
… Vince Hanada