Hello
A squeezebox into..? Was it a modded squeezebox?
A Panasonic XR57 digital receiver (the one I bought at a flee market for $125). No mods - in my opinion I don't need them.
I use the same squeezebox on my higher end system and no mods are required. I am running the digital out into an AVA Vision DAC that uses a Wolfson 8742 digital chip set. I use this same DAC with an inexpensive Denon CD player as well.
In either case, it is the quality of the DAC that determines the quality of the sound.
If there were problems with the transport, they would be found in two areas: data errors and/or clock jitter.
Data errors are almost non-existent. There is enough error correction built into any CD transport to almost eliminate data errors. If this were not the case, computers would not be able to run properly as software is often distributed on CD's and bit-for-bit accuracy is mandatory (computer transports are not normally high-end either).
With the Wolfson chip in the Vision DAC, clock jitter is not really an issue. If it is really bad, you may be able to see it in radio frequency measurements, but not in audio measurements. The chip set is optimized to virtually eliminate audio distortion due to any clock jitter.
So...if you have a good bit stream feeding a good DAC (and both the Squeezebox and Denon are certainly good enough to provide a good bit stream), the resulting sound quality rests almost entirely with the DAC (in this case the Wolfson, which is one of the best). Nothing you do to mod the squeezebox and no change in the CD transport itself will have any effect on the sound quality put out by the DAC.
That is my opinion based on the engineering involved. If someone can provide a demonstration, in the form of a blind test, that an expensive transport can provide better sound quality, I am all ears. But until then, I prefer not to drink that cool-aid.
Again, just one person's opinion and not necessarily the final word on the matter.
- Jim