Break in of Link DAC III


I purchased a link DAC III with half nelson upgrade a couple of weeks ago. I'm not overly impressed with it so far. While it is an improvement on my Rotel RCD 971, it's not night and day like I had heard in the audio store. I understand that break-in is required, but just how long are we talking here? So far, i have about 50 hours on it. Will there be a significant improvement in overall sound?

Associated equipment:
Rotel rcd971
Nakamichi AV10 top of line surround receiver (I suspect this is part of the problem)
NHT 2.5i speakers
KimberKable DV90 (i think that's it - silver coax cable)
audioquest type 4 speaker cable.

I'm starting to think that I got scammed into paying for a half Nelson upgrade that was never done. In other words, i'm worried that I just have the base model WITHOUT the upgrade, but that I paid for the upgrade (i'm not that trusting of the dealer - he seems like a scammer).

Main questions that need answering are:

1. Is break-in a significant improvement in sound quality? and if so, then how long does it take (and will it be a 'sudden improvement' or just gradual)?

2. How can I check to see if I ACTUALLY got the half Nelson upgrade?

any help for my worried mind would be appreciated...

Steve
loose
Do you have the P1000 Power Supply? The P1000 made a big difference to my DAC III. Also switching from Toslink to Coax input helped a lot.
Nope, I don't have the p1000. Can't afford it yet. The dealer I bought it from said that the difference between using the p1000 or not is like the difference between upsampling and no upsampling (in terms of degree of improvement), so I opted to go without the P1000.

I do, however, use coax and not toslink... I use the KimberKable D60 (sorry, i posted DV90 earlier - oops!)

Thanks for the input..
Open it up and look. From http://www.stereophile.com/showarchives.cgi?276:

"The Full Nelson version—named after Carol Nelson, the MSB sales rep who arranged to get the mod into production—transforms the unpretentious Link III with wholesale component swaps that preempt much of what the cottage-industry modifiers do for a living. The major effort is put into the analog stages, including using 2% Wima PP caps in the output filters, 75-ohm low-inductance Caddock ceramic resistors, and ultra-high-speed AD827 precision op-amps. Signal-path resistors are replaced with Roderstein 1% helical metal-film resistors, and the internal PS rails are upped from 8V to 12V. Finally, an AES/EBU digital input replaces the TosLink of the stock Link III. The Half Nelson version ($385) includes all of the above enhancements except for the AES/EBU input."