That's why I've stuck with the internal DACs on all my digital kit. If they're transparent, then they'll all sound the same, by definition, and if they sound different then they can't be transparent so I wouldn't want to use them.
So far, I've not found one DAC that wasn't transparent, but then I've kept away from tube or Non-Oversampling, unfiltered or any other engineering aberration.
What I would do if the budget isn't flexible is to put up with the inconvenience of individual side/rear mounted volume controls until you can save up for a simple passive volume control, or inexpensive pre-amp, for around £50 or so. Depending on where you're located, you may be able to find somebody helpful who can wire you a simple 'pot-in-a-box' which will do fine as a volume control.
I started out with an LP12, a B200 and MC2s (a mate of mine still the amp and speakers). I had the A100 with them for a while - a great amp. I remember the XA series fondly, still have an X-AS100 power amp.
The only item I haven't at one time owned from that list is your Tri Vista dac, but I heard one and it was great. I hope you enjoy it! The glowing feet from my KW days always reminded me of the BMWs we used to see apparently floating around Brixton on a pool of blue light....