I can't tell the difference

I have a primate I21 integrated amp, bowers and wilkins cm5 speakers, and a slim devices squeezebox. I recently purchased a musialcal fidelity v-dac thinking the squeezebox's dac might be my weak spot. I've done a blind comparison between the sb3's dac and the v-dac but I can't tell the difference between the two.

I really thought that the v-dac should have been a significant upgrade seeing as how it costs the same as the sb3 which has a lesser burr-brown chip and a ton of other componets where with the v-dac you are just paying for the dac and nothing else.

Should I be able to hear the difference here? How much do I need to spend to upgrade my source?
Mustard, let me unload a well known message here: break in, break in. How much time did you grant the V-dac before critical listening? I know it's hard to grasp how long fine dacs (no moving parts, only kind of electronic alchemy) need to come to themselves.
I did't hear the V-dac and have not read owner's reports concerning its break in characteristics, but, given how unresolving and unengaging the SB3 dac sounds, I would be surprised if a well burned in V-dac didn't lastly lift sonics quite a bit here.
When new, even seemingly simple units like the Valab dac need a week of constant converting work, after which it likely outperforms Lavry DA10 or the Transporter dac, as my ears were inclined to tell me.. As does, to a still higher degree, the new Wadia 151 in my system - and similarly, only after a week of having run continuously.
Well, all this burn-in talk might be old hat to you! Sorry in that case. I just wonder how many machines are being judged, sent back or reported on ahead of due time.
The V-DAC has about 40-50 hours on it. I have another couple weeks or so before I have to make a final decision on it, so I can give it a little while longer and do another blind test. My speakers are also very new so they may open up some also. I'm more willing to accept that the speakers will benefit from more time than I am the DAC, but I'll let my ears do the talking.

I'm pretty new around here so I'll try and keep an open mind. That said I'd like wade through the hifi voodoo at the same time. I'm also willing to accept that my system might not be revealing enough for me to pick up on certain things. I don't have the experience to know at this point.

Thanks for all the input.

Here is a link to a positive review of the infamous Tice Clock. LOL!!