McIntosh MC60 vs MC30

My mc60 doesn't have an inductor inside... it's a first version?

The "small transformer" is an inductor, used in power supply filtering. With tube amps, any power rating issues are relative. MC60s are not twice as powerful as 30s. I am not familiar with your speakers, but if they are efficient, an MC 30 would be a good match.

both sound very different. It is like comparing to MC275 to MC240. The MC60s has more power to drive the bass than th MC30. In our 5 diffent setups, the MC30s are not even as good as the MC240. Turn back in time, the speakers were much more efficient then so high power were not really needed in most setups. MC30s was popular because it was much cheaper and enough power for most of the application. Aside from that, the MC60s are one of the best Mono amps made by Mac from that era.