CD transport vintage and mods -

I recently decided to have Dan Wright of ModWright.com modify my 1994 CAL Delta transport. So as not to be without music, I purchased another CAL Delta on Audiogon, this one of 1995 vintage. Before sending one off, I did a comparison and of course they sounded different (everything else being exactly the same). The '94 seemed a bit more tight in the bass/lower mids and very coherent with respect to fundamentals and harmonics. This gave piano a very believable percussive quality appropriate to hammers hitting strings. The newly purchased '95 had a more refined and detailed sound (I might even call it sweet though I'm not sure why). Subtleties were revieled that I didn't hear with the '94, but the '94 had a solid feel (perhaps even PRAT). I decided the '95 was the unit I would have modified. - WOW! - The clarity, musicality, focus, and sense of being in the same room with real acoustical instruments is simply stunning after the mods. (I listen to a lot of cello and piano.)

There are actually two parts to this post:
1. I found that replacing the laser transport mechanism and doing modifications per Dan Wrights recommendations (installed a Bybee filter at the AES/EBU digital out., upgraded signal wire at digital out to Cryo-treated Jena Wire, upgraded all rectifier diodes to ultra-fast soft-recovery diodes, upgraded all critical power supply capacitors to Elna and Black Gate capacitors - increasing overall power supply filtering significantly, upgraded balanced digital out signal path resistor to a 110 ohm Vishay, and upgraded key voltage regulator serving digital out buffer to Audiocom Super Regulator) to have provided the best sound I've ever had - well worth the cost.
2. My experience with the two CAL Deltas has made me wonder whether or not our discussions of equipment are specific enough in describing our results. Since it makes sense that a given model of equipment is undergoing changes from one year to another, its not really possible to say that a CAL Delta (in this case) has a particular sound. Though I chose the '95, I have no doubt that others may have chosen the '94 as preferrable. It wasn't an obvious choice. One was not better than the other, they were just different. Have others heard sonic differences among different vintages of the same model of equipment?
(YAF - Yet Another Factor in our system development process.)