So let's try to make this less confused *. Here are some of my points:
- This Esoteric clock and other's like it are not the wave of the future IMHO. They are more 'band-aids" trying to correct issues of our past way of doing digital transports and DACS with that horrible SPDIF connection!
- The future of "amazing sounding digital" (read; As good as analog, if possible) will be coming from manufacturers NOT using SPDIF connections, or Esoteric re-clockers, but from OTHER forms of connectivity, such as USB.
- The "non-technical" reason that helps an audiophile "wrap their head" around the reason a USB connection can have the ability to sound much better is do with the fact that it doesn't interleave* clock signals on top of music data like the SPDIF format does.
*Please note; the above statement is a VERY SIMPLIFIED way of explaining this point. Not all of us went to engineering school! I will attempt to explain the technical detail in my direct response to Agear below;
Warning, the rest of this posting is VERY LONG.....
Yes Agear, your statements are absolutely true "in form". There is quite a bit of engineering "tech speak" that I didn't explain to Audiogon readers (such as yourself) who actually understand the detailed technical side of digital interface methodologies and their inherent topological underpinnings.
Such as;
-The clock signal itself on a USB is much different than that of a clock on a SPDIF. So much so in fact, that many engineers don't even think of it or label it as a clock anymore as compared to "the clock" within a SPDIF connection methodology. Here are some reasons why they think this way. The timing is sent on the USB sort of like a "when to start" signal. Sort of a "Hey USB! You are going to get a stream of digital data in the form of bits, now GO!" This is not the same as a clock being put on top of a continuous data stream like in the SPDIF. That is where the HUGE difference is that supports the "interleaving" statement. It also explains why you aren't having the major sync ssues associated with SDIF. In the end though we are talking about the actual interface between the transport and the DAC's input receiver and the inherent connectivity downfalls associated of the actual "clocking" data itself, how it is configured, how it is married to the data stream and how that clock information is different "in form" as opposed to a SPDIF and it's real ugly sonic mess comparably.
Both USB and I2S connectivity are a superior way of connecting digital transports and DACS than SPDIF comparably. The conversion to I2S can actually happen in a properly designed USB Dac too. This conversion to I2S would happen later time in the digital chain itself. With this in mind, I do think we need to think of a properly designed USB DAC as having I2S (it just starts with USB cable before I2S). What does this all mean to the comparison of USB versus I2S connections if we convert earlier in the chain as opposed to using a simple computer USB connection? Well, that is where the sound quality itself will show the merits of both of these connectivity methodologies. Here are my thoughts ; since a computer has a built in USB connection, it makes it much more straight forward to connect the computer via USB to the DAC (Can we say "elegant"?). It also makes it easier for the audiophile to hook up (Can we say "simple"?) There is less cost associated with the USB connectivity (Can we say "We like to save money"?). Lastly and most importantly; the most impressive DAC I've ever heard up to this point was a USB Dac. That is where the "proof is in the pudding" for myself. Whatever format gives us the best sound and is actually closest to analog is where are measuring stick should be. All of these technical "explanations" and "tearing down" the engineering side of digital is interesting but the end sonic result is what really counts IMHO (not necessarily the technical methodology).
Since Agear pointed to Steve Nugent, I'll let some of Steve's statements outline what I've been trying to convey also (this information is from Steve Nugent himself):
"In an outboard USB converter, the data is received from the sending computer and precise timing information is added. The jitter from the computer clock can be effectively eliminated. The interface is then translated into an interface that a DAC can understand, such as S/PDIF, AES/EBU or I2S (the native DAC chip interface). The clock that generates the timing can be very precise and does not depend on data rate coming from a rotating optical disk, like a CD player, or the rate at which a hard disk is read. It does however depend on uninterrupted data flow from the computer."
