Can upsamplers alter a CD's sonic performance?

Last August I posteed a thread asking if a CD droped into a transport tray hooked to an upsampling DAC would saidCD sound significantly better. Well, 2 weeks ago I bought an Electrocompaniet ECD1 192 upsampling DAC and hooked it to my MAC 205 player. It was a demo so the unit was burned in. WOW! What an unbelievable improvement in the sound of my CDs. I just can't say enough to express the changes this upsampler made!

i read in a canadian mag that they upsample to dsd before playing. well, my ns500v sounds better as a cdp than my original setup (philips cdr/alchemy ditb) which sounded fairly good to begin with. my 20 yr old daughter noticed this on her CDs also and reinforced this when i mentioned it to her. i believe it was an incubus cd that she said she thought someone was in the next room where the player was. at any rate, i like the sound of my ns500v especially at the price of $161 delivered.
.......regards.....tr

Hello Pls1, can you please expand on this. I can't quite follow.

"The reason that upsampling improves the sound is that it allows the DAC to convert the digital info to analog with fewer added artifacts that are a result of the DAC's internal conversion algorithms and filters"

- How is it converting the digital to analog with fewer added artifacts?
- Where is the analog signal goes from there?

"These added analog artifacts (which are NOT part of the original CD's encoded data) make the analog signal sound harsh and congested. "

- Where is the upsampling come-in? Will it clean out the artifacts while the signal still in digital or analog?

Thanks, William

ISTT