The PSU differences alone are significant and the reason why an amp given the same circuit (more or less) can sound different from it's larger brother (in terms of PSU complexity and quality)...the same is also true for the DAC and transport....let me be clear on this...PSU quality can often make the difference from an ordinary performer and an extraordinary one (given roughly the same amp/dac topology on the back end).
The old saying goes...the first 3 aspects of design and modification begin and end with power supply, power supply and (uh, yep you guessed it) power supply. That all being said any combo device IS an exercise in compromise, it all depends on the ambition of the designer , the size of the chassis and the targeted price point. I have long been a separates guy (and for good reason). I feel it is the pinnacle of performance and nuanced expression with this performance being, usually, the sole domain of the purpose (over) built single use devices. That is not to say that there can't be exceptional combo devices (there are some worthy of Class A distinction) but they usually cost almost as much (or more) than their separates brethren. Integrated amps are a good example of what I would consider an acceptable compromise if one needs to combine attributes but I will always go for separates when it comes to sources (especially so when it concerns digital) as this part of any system , I feel, it is the key to it being terrific, ordinary or awful (depending largely on the quality of power supply)...I'm a "source is king" kinda guy when it comes to a "whole system". I also believe the transducers (cans, speakers) are equally important...sort of like bookends, with a solid set of bookends and quality pieces filling out the middle the end result should be great (if you carefully match all the pieces of the puzzle). I know it's deciding how to match what puzzle pieces complement each other that is the hard part but with a little experience and a lot of digging (reading/research) it's not that difficult.
One thing i always wondered about PSUs; i can understand their importance in an amplifier design due to large voltage swings, especially when listening at higher volumes. I can easily see why having the extra PSU reserve & headroom would be a benefit to SQ. However, when it comes to a DAC with an unamplified line out signal of only 2V, why would it matter so much to have such extensive (multiple) power supplies? My decision (in part) to draw the line at the DAC19 (compared to the DAC-3SE with 3 massive power supplies for example) is because i felt its PSU was sufficient for what the unit does (other reasons were the added connectivity options). I must be missing something?
Sorry for OT.
Edited by vlach - 10/25/10 at 10:32am