Tube Rolling - Any tips or caveats


I recently purchased an ARC SP-16 and have decided that I would like to upgrade the tubes, essentially I will begin tube-rolling.

I purchased some NOS tubes to replace the phone stage tubes, but before I do, I was wondering if anyone has any tips or caveats regarding tube rolling. Things such as:

- Should I A-B test different tubes, swapping in/out quickly?
- Can I mix & match brands, or NOS vs. New etc...?
- Should I start from source and move downstream (ph-stage, Line stage,... power amp) or vice versa?

In general any tips would be welcome.
nick_sr
Get VERY familiar with the sound of your pre-amp with stock tubes. Make notes of the areas that you would like improve i.e. more impactful bass, extended highs etc. Once you have a list of attributes that you wish to improve, research for a tube that exhibit said traits or post on this forum for tubes suggestion i.e. looking for a 12AX7 with extended highs etc. When searching for NOS tubes you must have a game plan and an objective, otherwise it becomes an expensive guessing game.
Thank you mofimadness for that link. That is a great article. My experince with NOS Amperex 6dj8's in my phono section mirror the comments in his article. A lot of good info in the world of NOS preamp tubes.
Thanks for the tips.

BRF, I know what I want, extended bass and more dynamics. I have already been lining up some reference recordings that I have been listening to for a while.

I have already purchased a pair of telefunken 12AX7's so that will be the starting point. I realized after purchasing them that the SP-16 has 3 tubes in the phono section. And I spoke with ARC and they suggested to leave in the stock tube at the input as it must be low noise. I also wasn't aware that there was a low-noise so I have no way of knowing if the telefunken are or not (other than trying them out).

Knowing the above, next time I will buy my tubes from someone sepcialized in tubes, as recommended.

As for the Mofi's Audioasylum link, it was very informative, but I am not sure I ready to switch to 5751's.
Other respectable tube suppierls are : tubemonegr; Tube depot & brent jesse - you can get good NOS tubes w/o spending a fortune
Be careful pulling out and inserting tubes so you don't mash the tiny plug in the ceramic tube holder