Lapierre makes an excellent point about matching tubes. Sound advice to follow.
I'm using a McIntosh C2200 as my pre and it is a great match for the 275 so I think your interest in the c220 is well justified.
I started on the tube-rolling path when I noticed my stock KT88s were pulsating blue light. It was weird because you couldn't see it looking directly at the tubes only out of your peripheral vision. I thought it was just my aging night vision until my wife noticed it, too. The stock tubes don't last more than a year, if that. But even if they're still good you will be rewarded with rolling to better tubes.
I'm using a McIntosh C2200 as my pre and it is a great match for the 275 so I think your interest in the c220 is well justified.
I started on the tube-rolling path when I noticed my stock KT88s were pulsating blue light. It was weird because you couldn't see it looking directly at the tubes only out of your peripheral vision. I thought it was just my aging night vision until my wife noticed it, too. The stock tubes don't last more than a year, if that. But even if they're still good you will be rewarded with rolling to better tubes.