McIntosh 275 and tube rolling, biasing

i just bought a mc240 and mx 110. amp has a broken tube the 6lc4 ? the big one of four -the amp in not here to check the # what brand tubes do you advise. shall i retube both pieces if the old tube check ok? i feel i should 4 new 6lc4's? matched for the amp. also is the mc240 autobiasing as well?

It's self biasing, which is good. One more headache not to worry about. One reason McIntosh outsold Marantz...

Sure, roll those tubes. But,if you have a MC275 with balanced inputs, and use them, you will hear virtually no difference. When you use the RCA inputs, you then put the first tube into the circuit. Changing that tube can change the sound of the amp. The MC275 is well know for it's design being such that it does not depend on the tubes for it's "sound". I have the 1997 version in stainless steel. I use the original McIntosh branded "Russian" built input tubes. I use the original McIntosh branded, Svetlana built, output tubes. The sound is impeccable! IMPECCABLE!
I also own a mid sixties built MC240 that still has ALL the original tubes. Sounds equally GREAT. It is rare for a McIntosh to use up the tubes. They build the amps to last and NOT overstress the tubes. I read about a lot of guys with "newer" amps of different brands always cooking tubes and having problems. No, I don't work for Mac, but believe in their products. What are you waiting for: BUY THAT AMP!