There seems to be a lot of false information circulating around the forums with regards to USB to SPDIF transports.
Many forum members believe the following:
1) Asynchronous is better than Synchronous/Isochrnous transfer methods
2) USB powered devices are inferrior in comparisn to battery powered and/or external linear power supplies
3) The transport with the lowest jitter measurement will have the best performance
Members are putting a lot of emphasis on the above, believing that if a transport has some or all of the characteristics it will be "the best"
It is simply not the case. USB to SPDIF transports could boast asynchronous transfer, battery powered and less than .0001 ps of RMS jitter and it could sound like crap in your system. Having these features does not tell you how a transport will "sound"
While asynchronous communication, external battery supplies and low jitter measurements have been "proven" to increase "performance", none of these things tell you how the transport will perform in YOUR system
It should be mentioned that all transports have jitter, for example CD players/transports. In reading through the forums its clear that not everyone seems to understand that jitter has always existing in audio transports, its not something new to USB. Do you ever hear discussions about the jitter measurments of CD players....
There are many highly regarded CD transports that do not have the lowest measured jitter in their price range, however still consistantly "score" better marks, or have more recognition of being world class.
What it comes down to is...design, implementation, and system synergy.
If a manufacturer decides to use USB power, with a design thats meant to work with "dirty power", designed to clean and restore the signal. Do you think it will be less effective than battery power?
If a manufacturer decides to use a non asynchronous transfer method, say for instance the transport has been designed to specifically work synchronously. Do you think they cannot design it to work as effectively as an asynchronous implementation?
If a manufacturer designs their transport, which gets amazing reviews....then people find out it was voiced with 500 ps of RMS jitter. Does it make it inferrior to a device that boasts 5 ps of RMS jitter. Does jitter indicate how a device will sound in your system?
In truth all of these things matter and none of these things matter. It all comes down to design and implementation. Remember not all transports will sound good mated with your DAC in your system, no one will have the same results.
People who go around comparing devices like the Audiophilleo, Diverter, M2Tech, Bel Canto, Offramp, Stello, Blue Circle, etc based solely on specs, not actually hearing these devices. Then posting in the forums spreading information like its fact when there is no truth behind what they are talking about.
Even then, its entirely possible that a Bel Canto will sound better than an Audiophilleo in your system and vice versa. There really is no "best" transport.
Its all about finding the a transport that mates well with your system, your DAC especially.
There is no way that anyone can prove that transport A is better than transport B because it will perform differently in different systems and each persons idea of the "perfect sound" is not the same as everyone elses.
Edited by sk3383 - 5/17/11 at 3:28pm