The C1100 and D1100 combo was my first McIntosh preamp and I haven’t been let down. If you have the space the C1100 will be sure to impress. Paired a 312 with those Guarneri speakers could be lovely. A C2600 is not a bad option at all, one box and would help save some $$.
If you want to go with tube amps why stop at the 275? What about a pair of 2301s
