MC901 monoblock tube matching Q

Nice the dream team 901's and C1100

My understanding is all Mac tube amps use a biasing system that obviates the need for matching either power tubes or pre-drivers.  But sourcing your tubes from them should be the safe bet. If their parts guy doesn’t inspire confidence, ask one of the more senior tech advisors like Chuck Hinton. 

Looks like @crustycoot is correct. I called McIntosh again, this time got Chuck in technical support. He said neither the power tubes or signal tubes need to be matched in their amps or preamps. He did say it’s possible there may be a slight audible benefit if using matched sets, however. Guess that answers my questions. 

Get yourself a couple of spares,and call it a day. Sit back,and enjoy the music. 

It makes no sense to change tubes on a brand new amp. I don't think Mac would put inferior tubes in their statement monoblocks. I have a C1100 with the stock tubes & the sound is fantastic. Mac tech support told me that preamp tubes are good for 5 to ten years.