On my IRS Betas I used 4 mono Jeff Rowland 7 and was very happy. I still use one pair of Rowland 7 for the Base towers , the top end I run a Pass x250 that works fantastic at low levels the detail and musicality is incredible however when pushing the amp to leave class A , quality deteriorates a little. (compared to some other power amps they just sound very bad when the speaker demands control).
Other Power amps I would consider for a IRS Beta system is
PassLabs 100.5 ,
Jeff Rowland 7 ,
Threshold has some option ,
MBL I always liked but was not convinced ,
AVM 8,2 would like to explore ,
Krell I never explore due to the harsh sound ,
Usher had some amp that looked OK but don't know enough about ,
Mcintosh I love the look and build but the sound never impressed me ,
Some old mark levinson ML 3
PS;
A. The biggest improvement in sound on my IRS Beta set up I got out of my pre-amp the Legend Audio L2 signature (now Von Gaylord Audio) and a DA from them plus interconnect cables. (=>tube for pre-amp!!!)
Tweaking the IRS Beta setup to be very revealing leads to most not perfect recorded music sound terrible , for that reason I have additional setups HHScott with Klipsch Corner-horn and a Legacy speaker with a Jadis amp.
B. While my amps were out for repair I had a workable experience with my old Yamaha MX1000 for the Base only (could not listen to it on the panels).
C. I used a MC250 (SS),MC 75 (tube), MC275 (tube)for the base as well but it sounded very muddy , your MC2100 may work for the base until you get something more serious.
Other Power amps I would consider for a IRS Beta system is
PassLabs 100.5 ,
Jeff Rowland 7 ,
Threshold has some option ,
MBL I always liked but was not convinced ,
AVM 8,2 would like to explore ,
Krell I never explore due to the harsh sound ,
Usher had some amp that looked OK but don't know enough about ,
Mcintosh I love the look and build but the sound never impressed me ,
Some old mark levinson ML 3
PS;
A. The biggest improvement in sound on my IRS Beta set up I got out of my pre-amp the Legend Audio L2 signature (now Von Gaylord Audio) and a DA from them plus interconnect cables. (=>tube for pre-amp!!!)
Tweaking the IRS Beta setup to be very revealing leads to most not perfect recorded music sound terrible , for that reason I have additional setups HHScott with Klipsch Corner-horn and a Legacy speaker with a Jadis amp.
B. While my amps were out for repair I had a workable experience with my old Yamaha MX1000 for the Base only (could not listen to it on the panels).
C. I used a MC250 (SS),MC 75 (tube), MC275 (tube)for the base as well but it sounded very muddy , your MC2100 may work for the base until you get something more serious.