Matching up speakers and amps

Based on reading about the DNA 0.5, & having one in one of my systems (with Spendor S3/5 SE's), I'd keep the McCormack--very nice sounding amp, unless you have very hard-to-drive speakers perhaps.

PS--what are you looking to do, i.e. what's bugging you about the sound now, etc, that you want to improve?

A possible upgrade for your McCormack DNA .5 is to try and score a used DNA .5 that has been upgraded by SMc Audio. Sometimes you can find them here on A'gon for about $900- $1000+. If not you can send it to SMc Audio for mods. Whenever I've spoken to Kris or Steve they always are willing to customize the mods to your needs and give you the most for your buck. To me if you are happy with the McCormack just stay along those lines.

I have no first hand knowledge of Spendor speakers, but I recall reading a review on Musical Fidelity's current M6 product line that specifically mentioned a couple of speakers that pair very well with M6 components. One of the speakers mentioned was the Spendor S9, so to the extent that the A5 may have similar characteristics to the S9, then the Musical Fidelty M6PRX amplifier would probably be a good pairing. The review I am referring to was by Alan Sircom and published at avguide.com.

I use the M6PRX with B&W 804 Diamonds, which is a combination that I like although it is not one that Sircom mentioned. I suspect a used M6PRX would be in the vicinity of $2500 or perhaps a little bit more. It's an outstanding amp that you don't hear much about, which is a little surprising given several absolutely glowing reviews.

The only caution I have about the M6PRX is that does run on the warm side so it's definitely not an amp that I would place inside any kind of cabinet.

Steveaudio: Actually, I have no issues with the sound of my system, just that I have had the McCormack and the Acurus pre amp for 13 years and I'm itching to try tubes!

You should go ahead and do that then. The Spendors have usually been tube-friendly.