? Modded Oppo 983 ?

Mjcmt,

Let us know how the DAC1 sounds - can you hear a solid imprvement or not? I note that Benchmark's DAC1 has a few years under its belt and yet lives on with high resale value - an almost certain sign of a good product. (I avoid bleeding egde latest and greatest and am a mere follower when it comes to products - many satisfied users with better ears than me and five or more successful years in the market without "lemon reports" is my weeding out - stay-off-the-merry-go-round selection process).

Yes, having its own power supply and chassis to isolate it from the vibration producing transport is a positive side of a stand alone DAC, not to mention the added versatility

I don't think it is the mechanical vibration isolation that is so much the benefit of a separate DAC. The problem is the secondary effects of the control system in a CDP player, which has to manage the transport (lazer focus/tracking etc.) Since the disc rotates there is a good chance to induce sinusoidal variations in the power demanded by the servos in the transport. Jitter is not such a bad thing if it is completely random, however, if you can imagine that the transport servos could be causing sinsoidal or cyclical power demands from the CDP power supply then it is easy to imagine how the shared power supply could subsequently induce a specific jitter frequency in the nearby DAC clock.

There are many ways to imagine this happening. If you turn up the volume loudly then the CD itself may vibrate slightly - inducing periodic control corrections in the lazer pick up. If the hole in the CD is not absolutely perfectly centered then during every revolution there will be a sinusoidal control signal sent to the lazer. If the metal layer within the CD is not perfectly flat or aligned within the plastic then this too may cause periodic corrections to be required. Ed Meitner stuck a CD player right in front of a speaker and demonstarted at least one of these jitter effects about 15 years ago.

Obviously before getting too worried - these effects are extremely small and most people are happy with an ordinary CDP - so many transports do not exhibit any of these problems - such as the extremely popular line of Cambridge CDP's, which sound great at a reasonable price. However there is probably a better than 50/50 chance that you find one of these problems in most low end CDP players.

On another note - it is good to see you are happy with your new toy.