200902191308Bryston BDA-1 DAC 評論 英文
Bryston BDA-1 DAC ReviewMon, 10/27/2008 - 01:25 — The Computer Au...
The Bryston BDA-1 external DAC has been one of the most highly anticipated products of 2008. I have received countless emails asking who, what, when, where, and why all related to the BDA-1. Many audiophiles have withheld DAC purchases for several months until the release and review(s) of the BDA-1. Fortunately those patient audiophiles will be very happy they waited for this DAC. Everything about the BDA-1 is first class. Computer Audiophile is honored to publish the very first official review, anywhere in the world, of the new Bryston BDA-1 external DAC.
Almost all audiophiles are familiar with Bryston and it's reputation for quality. What many audiophiles may not know is that Bryston is a very non-pretentious down to earth company. James Tanner of Bryston can often be found perusing Internet forums answering questions from current and potential customers. James has also been known to ask these same people what they want in a product. In the land of Oz that high-end audio can sometimes be, this is downright cool. I'm also willing to bet that James would have a beer and watch Hockey Night in Canada with a potential customer and only talk "shop" if the topic came up. Bryston doesn't have to be pushy, or make up questionable statements to sell products. Bryston products, including the new BDA-1, sell themselves.
The BDA-1 has some very tough siblings to follow. The 28B SST amplifiers have received major accolades and the BCD-1 CD player was given the Golden Ear Award from The Abso!ute Sound this year. Having listened to all three of these products I know without a doubt the BDA-1 lives up to the family name. In typical Bryston fashion the BDA-1 has great specs. This DAC is not a BCD-1 with the disc drive removed. The BDA-1 has two independent linear power supplies and dual Crystal CS-4398 DAC chips. The inputs on this unit are almost endless. One USB at 16Bit 32K-48K, two coax, two optical, one AES/EBU, and two BNC all at 16-24Bit and 32, 44.1, 48, 88.2, 96, 176, or 192K. Sure there are additional inputs Bryston could have included but this is not some sort of all-in-one digital switching box. If you can't connect this DAC to your existing computer and/or audio system you've probably got a PC running Windows 3.11 or your stereo is still a piece of furniture passed down from Grandma and Grandpa. Nothing wrong with a nice sofa-sized all wood stereo, but I think it's time for an upgrade. The outputs on the BDA-1 are Bryston's standard fare, both single ended RCA and balanced XLR. There is an additional coax digital output that bypasses the DAC completely and sends out an untouched digital stream. I used this to verify bit perfect data by outputting audio to my Berkeley Audio Design Alpha DAC. The BDA-1 passed the audio signal bit for bit every time.
Jitter is one of the more elusive concepts in high-end audio. Bryston's website explains jitter in this easy to understand way.
"Jitter is a mistiming of data being moved from point A to point B in any synchronous digital system. Think of jitter as individual ticks on a clock—however each tick is not occurring at exact one-second intervals. Some are slightly less than a second and some are slightly longer, and they average out so that no actual time is being gained or lost over a large number of seconds. Jitter is the difference between the shortest and the longest second, and in digital audio systems this specification is usually measured in nanoseconds. Both the frequency and the jitter characteristics of the system’s digital clock will affect the accuracy of reproduction. The frequency, if not accurate, can cause the pitch and speed of the music to change, and in some systems cause drop-outs if there is no data available."
To reduce jitter Bryston doesn't go way overboard and require the DAC to rest on one ton of natural granite. Bryston simply re-samples and re-clocks the input to reduce jitter to 1/1000 of a nanosecond. I use the term "simply" only as a figure of speech. There is nothing simple about Bryston's solution to jitter reduction and it works wonderfully.
Bryston's up-sampling approach in the BDA-1 is marvelous. To satisfy the "purists" I'll get this out of the way early. There is an up-sample bypass button on the front of the BDA-1. The "purists" can now pass Go, collect $200, and proceed to the next paragraph. The rest of us will be interested to know that Bryston put some serious thought into its up-sampling. The highest number is not always the best and can actually degrade the sound quality. This is why Bryston up-samples based on the input sample frequency. Multiples of 44.1k are up-sampled to 176.4k and multiples of 48k are up-sampled to 192k. This synchronous up-sampling process has at least three major benefits. First up-sampling improves processing by the DAC because it was designed for greater bit depths and higher sample rates. Second, the up-sampling process shifts noise to inaudible frequencies. Third, up-sampling produces a new clock signal that reduces jitter. The choice to up-sample is left entirely up to the listener. My preference when listening through the BDA-1 was to bypass the up-sampling feature. The major difference when electing to up-sample was very subtle but still audible. There was an almost tube-like euphonic sound that could be described as Hi-Fi with an artificially wider soundstage. Without the up-sample bypass option it would be nearly impossible to notice this very subtle difference. To put it another way, if the DAC auto up-sampled everything without a bypass feature listeners, myself included, would be hard pressed to hear anything like I described. That's how subtle the sonic difference is between up-sampled and non up-sampled output from the BDA-1.
The most overlooked piece of all DACs is the analog stage. What I mean is consumers frequently don't take the analog stage into consideration when researching a DAC. People get very caught up in the specs of the DAC chip and achieving the highest sample rate possible and forget that the analog stage is just as important. The best DAC chip in the world will be reduced to an unimportant level if the analog stage was weak. One picosecond of jitter really wouldn't mean much with the audio flowing through a flawed analog output. Fortunately many manufacturers don't overlook the analog stage and Bryston is no different. Bryston says the analog stage is the most critical part of the BDA-1. This is why it used proprietary Bryston Class A discrete op-amps rather than commonly used IC chips. This design allows Bryston to match the needs of the DAC instead of using a standard integrated circuit that would force it to compromise the design. This is somewhat similar to an active speaker that has been matched perfectly to the power amp inside the speaker cabinet. When both parts of the system are under the control of the designer the results can be very good.
Bryston build quality has always been legendary and the BDA-1 is no exception. The DAC is very substantial and the solid aluminum faceplate is an eye catcher. The Bryston logo etched into the aluminum extrudes quality and attention to detail. Why screen print the Bryston name on the front when you can just carve it out of the aluminum! When many other manufacturers are seeking ways to cut costs, Bryston is insuring every ounce of quality is kept in its components while still keeping prices extremely reasonable. My favorite detail on the front panel is the sample rate indicator lights. Every sample rate from 32 to 192k is available. If you forget to set Audio Midi on your Mac to 24/176.4 when listening to the Reference Recordings HRx albums the BDA-1 will be there to remind you that your listening with the incorrect sample rate indicated on the front panel. Another nice touch is the up-sample indicator light and its color variations. When bypassing the up-sample feature the light is off. When up-sampling to 176.4k the light is amber and when up-sampling to 192k the light is green.
Now for my traditional gripes about the product I am reviewing. If I was granted one wish and Bryston would make it happen, I'd wish for a volume control. This would allow listeners to bypass a preamp & associated interconnects and go straight to their amp(s). Preamps are filters and the less filters in the audio chain the better. It would also be nice if Bryston included a minimal remote control with the DAC. But, most users probably don't switch inputs as much as I do during a review and a remote would increase the price of the unit for everyone even if they did not need the remote. A Bryston remote is sold separately and it can control a host of Bryston components. Since these are the only two gripes that come to mind I think Bryston has done a very nice job designing and building the DAC-1.
All source material while listening through the BDA-1 was AIFF or WAV files using iTunes on a Mac Pro desktop.
The Bryston BDA-1 external DAC is one solid component in build quality and sound quality. Accurate is probably the adjective that comes to mind first when I think about the BDA-1. The DAC is just plain accurate. Putting the BDA-1 through the wringer of 24/176.4 HRx material really showed its worth. Crown Imperial from the Dallas Wind Symphony (RR-112 HRx) was reproduced wonderfully through the BDA-1. A sure sign that I like what I hear is when I don't get distracted and I sit through the whole performance without thinking about what to put on next. For me to sit through a complete classical performance without pain is something special. During the BDA-1 review I certainly did sit through the whole Crown Imperial album and enjoyed every note.
At Rocky Mountain Audiofest I dropped a considerable amount of money at the Mobile Fidelity booth within the first ten minutes of the show opening. One disc I purchased was Natalie Merchant's Tigerlily. I ripped it to my Thecus 5200B Pro NAS drive when I arrived back in Minneapolis and I've been listening to it frequently. Listening to Tigerlily I can get a good feel for a components sound signature on Natalie's voice. Track one San Andreas Fault and track four River sounded superb. Natalie's rich voice was reproduced incredibly accurate. Having attended many Natalie Merchant concerts and listening to her albums on every system imaginable I have a pretty good feel for what I believe is an accurate reproduction of her voice. The BDA-1 was spot on with Natalie.
One album I have been addicted to recently is Consolers of the Lonely from The Raconteurs. You wouldn't think a hard rock recording like this would really be the best test of a system or DAC's quality, but surprisingly sonic differences are readily apparent with this album. The title track has some great guitar and drums all the way through. I brought this track to many suites at RMAF 2008 and heard some impressive results and surprised many people in the room with my choice of music. Needless to say I've also heard this music on many high-end systems. The key to reproducing this recording well is the bass drum accuracy. On some systems I can't make it beyond the first minute without turning the track off because the bottom end is so loose. For example, last weekend I listened to this track through a six figure system comprised of Wilson Maxx 2 speakers and several different components from Ayre and Wadia. I played the song 1.5 times to make sure I was really hearing what I thought I was. The second time I didn't make it through the whole song. The bottom end was not doing it for me. With the BDA-1, granted in a different system under different listening conditions, I have listened to this track and album so many times I've lost count. If it was possible to wear a grove into a hard drive I probably would have done it where this album is located on the drive.
The BDA-1 is not a perfect DAC in terms of sound quality. My biggest issue is the soundstage. Compared to my Berkeley Audio Design Alpha DAC ($5000 MSRP) the soundstage through the BDA-1 is closed-in. The Alpha DAC reproduces an incredible three dimensional soundstage that I've never heard through any other component. So, for the BDA-1 it's like coming in second place to Michael Phelps at the Beijing 2008 Summer Olympics. Second is not a bad place to be considering the first place winner is the best in the world. Even though the soundstage was quite a bit more closed in compared to the Alpha DAC, I consider it right on par with the Weiss Minerva via its FireWire interface. The BDA-1 remained extremely accurate with very good upper extension and very tightly controlled bottom end. Another sound quality issue arose when I used the optical input and up-sampled. I thought the sound was a bit brittle and female voices were less appealing. Just like my other observations with up-sampling this was extremely subtle and only noticeable because I was testing every input every which way but loose. Plus I was comparing them all to the Alpha DAC.
Listening through the USB, optical, and AES interfaces brought out some subtle differences. My favorite interface in terms of sound quality was the AES via my Lynx AES16e card and Mac Pro. The AES interface in the BDA-1 accepts up to 24/192 audio. This allowed me to listen to every sample rate in my collection without downsampling at all. The USB input offered great sound as well although a little short of the performance of the AES-Lynx combination. If I only had a USB port on my computer to connect to the BDA-1 I would not hesitate one bit. The sound quality was 99% of what it was through the AES-Lynx interface. The accuracy and tightness of this DAC is all there through the USB 16 bit / 44.1 kHz input. In fact the BDA-1 is a major step forward for computer based music because of its USB interface. More and more manufacturers are talking about USB interfaces but Bryston's BDA-1 has one right now and it sounds fabulous.
Bryston has built its reputation over the years by building great products. You'll never see outrageous claims from Bryston like the BDA-1 will make you look thirty years younger. However, when you play back some old Steely Dan through this DAC you may very well feel thirty years younger and like you're at a live show. The BDA-1 does not offer a Scratch n' Sniff feature for the full live concert smell, but it comes very close to live music with great sound quality. The Bryston BDA-1 external DAC is an incredible bargain at only $1995. The sound quality, build quality, and feature set are equal to or better than other DACs I've heard at twice the price. That's not a review cliche, that's the honest truth. In private conversations during the review period I described this DAC as a giant-killer. I stand by those words and advise many DAC manufacturers to steer clear of a DAC shootout with the BDA-1. If I didn't own my beloved Alpha DAC I would have purchased the review sample in a heartbeat, and saved $3000! As I box the BDA-1 back up and ready it for the trip back to Ontario, Canada I wonder if my wife needs a DAC for her iPod Shuffle?
Look for the Bryston BDA-1 on the CASH list very soon.
Note: Bryston currently offers its products through a large dealer network. If you live out in the boonies Audio Advisor offers the BDA-1 at the same price as a local dealer.
Associated Equipment: Mac Pro, Lynx AES16e card, Berkeley Audio Design Alpha DAC, Benchmark DAC1 PRE, Kimber Select cable, Avalon speakers, McIntosh tube amplification, Virtual Dynamics power cables.