McIntosh tube upgrade - worthwhile?

@wbs 

Thanks I looked for it and actually ordered it. Any chance you could share what might've been said about amplifiers effect tubes and anything else about the depth of info they go in to about McIntosh amplifier.

The book is really The Mcintosh Story.  Mr. Kessler did a lot of interviews and covered a lot of ground, so IMO there isn't a lot of real depth about circuits or individual products.  It's more of a journey than a textbook.  It did reflect the goals and directions that the company aspired to and what they were trying to achieve when developing new products, and how they perceived their customer's wants and needs.  Lots of good pictures.

It's been a few years since I read this book and I would have to research it myself to give you detailed info.  If you have ordered it you will soon be able to read and form your own opinions which will be better and more accurate than me trying to remember.

Bill

Just to add--I am a Mcintosh owner and fan and although I quailed at the cost of this book, it turned out to be a good read and no regrets.

Bill

swapped out stock tubes for NOS from the 30's and 40's.  no discernible change to my ears, but did experience a discernible decrease in wallet thickness.  Now other tube amp?  striking difference when using quality NOS tubes.....why?  no clue.

I own a MA 12000 integrated. It has 4 tubes in the preamp section. I too wonder if swapping these tubes would make a difference! Where does go besides Uncle Kevin for quality tubes and the right ones???