Importance of computer for DAC shootout


I am using a perfectwave DAC + bridge + modwright 36.5 LS/PS preamp to stream flacs over my network. Very happy with the sound, but intrigued by the idea of getting better SQ for less $$$ I will soon be auditioning an Antelope Zodiac Gold + Volticus over USB, directly into my poweramp. Being able to take out the modwright alone would pay for the new DAC. My only concern is the Computer I will be using for this shootout. I have a Dell laptop and an Asus media PC, both with USB 1.0.

If I opt for the Zodiac I will go all out on computer source (may be mach2music), but I don't want to invest before knowing if I even want to go down the USB path.

In you estimation, is there any chance of the computer used in my shootout distorting the outcome? Would I be better off using my Marantz ud9004 S/PDIF source for the Zodiac, and then get a better computer if the Zodiac wins the contest?

Or are the difference between computer sources small and will I be able to conclude which is the better DAC using a mediocre PC as the source for the Zodiac. Any advise on how to set up the hardware for the shootout is welcome.
edorr
I am using 2 PS audio P5 regenerators, which provide isolation. I would assume this should be OK.
Have you considered using a network player like Squeezebox Touch as the source to the DAC?

That would effectively take the "computer" out of the sound making process. Squeezebox is designed for use with good audio gear. Most home computers including laptops are not.

You would connect the network player to teh network either using a wired or wireless network connection and then the player streams the music files over the network from the music server (ie your laptop running the media server program, say Squeezeserver in teh case of Logitech Squeeze players) as needed.

That is what I would recommend to take the computer out of teh music making process. I have used this configuration with everything from a 8 year old Dell laptop to much newer laptops as the server and do not hear any audible differences, although I would recommend a faster or more modern laptop with 4Gb of memory or more in order for server related operations like music library scans, searches, etc. to run faster.
Never thought about it. Call me an audio snob but I am deeply sceptical of $300 devices being able to perform at the level of mac based music server architectures, used by computer audiophiles the world over.

Now, if they stuck their product in a heavy brushed aluminum box, called it the "Squeezebox reference" and charged $2000, I would definitely have considered it :) (provided it would accept a $500 aftermarket powercord of course).
"Call me an audio snob but I am deeply sceptical of $300 devices being able to perform at the level of mac based music server architectures, used by computer audiophiles the world over. "

Well, one is entitled to be skeptical but I suspect that one would be mistaken.

What is it exactly that makes a mac based music server architecture so special again for audiophiles?

Actually the DAC in the latest Squeezebox Touch specifically is rumored to be pretty good but I have not even tried it in that I had my DAC nailed down prior to going with the Squeeze devices.

A Mac based music server is fine. Squeezeserver runs on Macs, PCs, and other OSs, so you can use Squeeze players and your DAC of choice with a Mac music server.

But if the "mac based music server architecture" is so good, why use a third party DAC at all? Just use the one in the Mac and be done with it.
We're going off on a tangent. I have a phenomenally sounding PS AUdio Perfectwave DAC, streaming over the network. I am just intruiged by an reportedy very good altenative DAC with analog volume control. I want to make sure the computer I use to feed the DAC over USB is not the "weakest link" potentially distorting the outcome of a shootout. To this end, I bought a used Mac for a price I can easily resell it for. I think I'm all set.