MC275 Tube Rolling...

Hi Jgiacalo,
I am a happy new owner of MC275, in fact, I like it so much that I am getting a second pair so I can run them in mono. I wonder in your experience, does using the Herbie tube damper "sucks" the life out of the music?

Right now, I like what the MC275 does in my system from mid to high, the sound is very sweet and lifely. The bass is not bad, but below 40Hz it starts to get a little 'loose'. My speakers are only 85db efficient, but one single MC275 can drive it to 110 db loudness easily. I can't wait for the second unit to arrive.

Thanks for sharing.

Made a decision that I am going to give the Genalex a try. Still want to know whats good to roll for the 12 type tubes...

I also realized that on the chassis it is printed 12ax7a. What is the difference between the 12AX7 and the 12AX7A? Will it be okay if I use a 12AX7 instead of a 12AX7A?

Genelexs are in three of my amps. Great tubes. Reasonable price.
Amperex ecc83 are the best of the bunch for sound and longevity. Also,can use-12ax7,12ax7a,7025,7025a,6681,ecc803,ecc803s, plus others.
Telefunken ecc81, slightly dark but very clear and clean. Also can use-12at7,12at7wa,12at7wb,ecc801s etc.
These tubes range from common use tubes to commercial to military grade.
You can pretty much tune amp to your ear.

Mullards, Telefunken and Amperex are the most common used for 12ax7 and 12ax7a in preamps and amps. Some tubes have higher gain or low microphonics with warmer or darker sound.

Magnumpi205 described it pretty well.