Hi Prof -
yep, they do all sound a bit different. Function of the way the wiring is done, chip used, power supply etc. as well as the designers choices about how to voice it.
What we pretty much know is that coming using a hard drive as a transport greatly improves sound quality by eliminating the problems that are inherent in a 40 year old realtime electro-optical-mechanical design.
And that second to the problems of variable spin speeds and lasers reading pits; the second biggest quality problem to date has to do with poor SPDIF implementation.
SPDIF and Toslink are legacy systems that will fade away over time - though that is probably a decade due to the lifespan of much of this gear.
Yes you can get a Toslink capable DAC and link it to your old CDP - but what's the point - the CDP is inherently quality limited and to buy a Toslink DAC now is to make a dead end investment.
What drives the consumer electronic market is volume. What has unprecedented volume right now is iTunes, iPod and iPhone. In the past 5-6 years, over 100 million consumers worldwide now have some or all of their music on a hard drive. Many only buy downloadable music. This is what is going to drive the technology going forward -
Keep in mind that 2 channel redbook format audio needs very little bandwidth - the current standards and technologies provide plenty.
That makes future proofing difficult since it is most likely that the next file transfer technology will be designed for broader bandwidth media and to be wireless.
Following this logic, for 2009 a DAC with USB and WiFi would be the ticket. To see beyond that wait for the next CES and the next Intel Developers Forum and Apple Developers Forum.
But in terms of what you can buy today with your budget, go USB. You are safe for at least 3 years which is darn good in this day and age. The market is just too big to move any faster.
ALSO As you point out, there are many headphone users. Keces just introduced their 152 for this market which combines the DAC, preamp and power amp functions in one small form factor. I am sure it sounds great; and I am equally sure you will see more of these kinds of designs coming from Taiwan and China.
Using Keces as an example most people are aiming at one market or the other - the issue of course being that headphone users don't need the kind of wattage that people need to drive speakers.
It will take some digging - look to the east.
As far as support - its tricky since shipping a product back to Taiwan for a repair and then shipping it back will cost a disproportionate amount of the initial purchase price. Coupled with the construction techniques used, outright replacement is probably more cost effective.
This is a situation where you query the supplier/manufacturer first about his policies. Chance are that if it runs for a week after it arrives, it will run for many years.
Its also a you pays your money and makes your choices thing - by giving up the traditional importer/distributor model and dealing with the manufacturer you get a lot more for your money. But you don't get the same kind of service that someone who manufactures in the US and has a dealer network can provide.
IMHO, the hot ticket soon will be an integrated amp with a USB DAC built in, sufficient wattage to drive the average speaker (whatever that is) and enough niceties like remotes and headphone jacks to compete with the other integrated amps in the market place.
Eliminating components saves money and improves sound quality. It also uses less space which is important in every culture but ours. And it is greener which sooner or later will make a difference.
