Tube rolling 12AX7As

There are two reasons to change tubes in an amp. 1) Improve quality of tube and 2)Change the tone of the amp. Different brands of tubes, both new issues or NOS, impart a distinctly different tone. To be sure you get the tube that is best for you, you will have to be able to articulate what it is you want to change.

To do this you will have to listen to your unit for a considerable period of time to learn its sound and know where to take it. So listen and take your time. Come back in 6 months or so and someone will be able to give you pertinent help.

Do so now and you will probably be wasting your money and will go through multiple tube sets before you accidentally find what you like.

I agree with Newbee, if your preamp is new, let the unit and the stock tubes go thru a burn-in period. Otherwise you'll never know the true sound of the preamp and how it integrates into your system.
If you're curious, open it up to see what brand tubes McIntosh has used in your unit. But let the burn-in happen first before tube rolling and during that period you can research the different brands of NOS tubes and their sonic signature.

Thanks everyone for the wonderful replies. I will be heeding the advice. A few things......

The C2300 is not brand new. I have bought it used, with the original owner lightly using it. It has about 10 hours of actual operating time. I am assuming that 10 hours is not enough time for burn-in of the tubes. That leaves me to question, what is a reasonable length of time? 30, 40, 60 hours??

Secondly, for the first few months I will using the C2300 only via the headphone jack. The reason being is now I have to save up for an amp. I slowly but surely want to have a complete McIntosh system, so I am aiming for a completely refurbished MC240 (recapped with updated power supply) or a modern MC275. So I hope this does not seem like a stupid question, but will further burn-in occur while only utilizing the headphone portion of the preamp??

Lastly, about 80% of my music listening is via vinyl. That is why I chose the MC2300, for its phono stage. So if/when I wish to tube upgrade, the MM phono tube will be my main concern.

Either way, I will wait a few months before doing any tube rolling. Once more TYVM everyone for the advice thus far and recommended web sites!

Brad,

a good plan you have there and I admire your patience. Make sure and place the type of tubes in the preamp section that you want to use to flavor your system and you may wish to consider neutral tubes for your phono stage.

Now, I may be setting myself up for a flame or two but there will be some who believe breakin wont completely occur unless your preamp is connected to an amp. They are wrong and likely still live in their parents basement. As a matter of fact, they probably just dropped their video game controller while reading this heresy! LOL.

Brad, I would not worry too much about performing any tube upgrades until you get your amplification sorted and acquired. If I'm not mistaken, the headphone amp of the C2300 is an op amp so the funds spent on NOS 12AX7's might be better utilized presently toward your fund to purchase an amp. In other words, the addition of either amp would be top priority over flavoring the output of your preamp, which you likely would not be able to discern through the headphone outs of a C2300. My 2 cents would be to save for a 275, the 240 being kind of an enigma....not as sweet and lovely presentation wise as MC30's and not as crisp and articulate as the 275 editions. Good luck with your journey.