Which Audiologic dac was the first to go 24 bit?

Rx8man - Hello - your comment about "special tubes" caught my attention, as I have been wanting to try another set in my M34 dsm, purchased here used a couple years ago. We will be moving shortly; so, while the system is taken down, I thought it would be the opportune time to install new tubes, since I have no idea about the previous history of the stock unit. Also, my owner's manual apparently is missing the "tube placement diagram" page. I've never purchased a tube in my life, but figured I would contact Andy at Vintage Tube after reading about him here on the forum, and then at his website. Would you be willing to share your "special" ingredients.
Thanks very much for any suggestions you might care to provide.
Best regards,
Tom

Hi Jeffcott - thanks so much for your detailed discussion. As I don't consider myself a "paying" customer, I didn't feel it right to infringe upon Mr. Ozment's time concerning tube selection. It's apparent that you gentlemen have spent quite some time and effort in the quest, so I am very appreciative of your willingness to offer your observations to this neophyte.

After the aforementioned household move, my 2 ch. system will reside in a dedicated room, along with the components finding a new resting position upon a Sistrum SP-4 rack - so I'm hoping that this will adequately address the isolation enhancement you feel is important. (As an aside, I recently made the acquaintance of a local Audiogoner thru the forum, and I'm sure he would attest to my current hodge-podge 2 ch/ HT arrangement - I'm chomping at the bit to get things set-up properly. It perhaps may be a mistake to make all these changes - room, rack, tube rolling, etc - at once, but am afraid I don't have the patience any longer to do it methodically.) I will also act upon your suggestion for using the tube dampeners.

And thanks for the offer - I'll be in touch via email.

Cheers,
Tom

Hey - thanks to all you guys who've responded about tubes here. I will never ceased to be amazed at the level of knowledge you fellas possess for this hobby. Talk about feeling like a ditch-digger at an Aeronautical Engineering Society luncheon - sheesh!
Have a great weekend ...
Tom

Powder - using a Jena Labs Valkyrie digital XLR between a Mephisto II transport and my M34 dac. I just kinda dove off into the deep end, so sorry to say can't really offer any comparisons. Other than to say all my CD's are quite listenable :-)