We had the T+A PDP 3000 which is one of the most remarkable disc players ever made, the sound on both SACD and Redbook is postitively captivating, giagantic soundstage, tonally smooth with great detail, in all of our years of digital testing the best sound ever from CDs.
The PDP 3000 is also an excellent dac, but the sound out of the USB input was very good, just not equal to the magnificent, jaw dropping optical playback.
The PDP 3000 was replaced with the newer MP 3100 so that player might have an even better USB input.
The Aqua Hifi Dacs have excellent USB input cards, so they sound marvelous via USB.
DCS and MSB should also have excellent USB inputs.
In our expereince most of the more modern dac designs absolutuly favor usb and perhaps ethernet, for many of today’s dacs the highest samping rates are still only USB based inputs.
Older Dacs that favor AES or Spdif are like the Jeff Rowland Aeris which was designed by Holm audio of Denmark close to 10 years ago.which was designed long before USB really took off.
Other holdouts from the infancy of USB are pro companies like Bekley audio, (Pacific Macrosonics, the HD audio disc guys,) there products were designed by engineers for recording studios where AES/EBU is the standard.
USB is really a consumer audio connection, due to the flimseyness of the conection, however, the USB cable can carry a ton of data fast. The issues with USB cables have a lot to do with the 5V power that rides on some of the cables as well as noise intrusion from the computer.
Hence the evolution of galvanic isolation, separate 5v power lines, power distruptors, very high resolution USB cards with extensive noise filtering, better power supplies and lower noise chips, better audio designed mother boards, and isolation of the components to filter out EMI and RFI couple these devices innovations and you have Innous and Aurender Servers to name a few.
Most dac companies use some sort of commercially available USB input chip from XMOS or a few others companies, sometimes with a lot of custom tweeks and sometimes not.
What is fascinating is how the USB input card issues are being addressed, our new T+A SDV 3100 HV is one of the world’s best dacs, and the product uses a 100% in house designed ultra high speed USB card. designed to allow a massive amount of data to flow into the machine up to DSD 1024 from an external source.
USB and Ethernet in our opinion are really the only ways to get to true high resolution digital and many of today’s best dacs may sound way better to you via upsampled PCM or transcoded DSD.
Dave and Troy’
Audio Doctor NJ Innous dealers