Best Value McIntosh Integrated Amps

Is there a big difference in sound quality with the Mac SS amps that have the extra transformer. Does this transformer alter the sound in any way, or just let you use almost any low impedance speaker?

I like my old MA6100.

I like my 252.

I’m curious whether there’s a huge difference or any difference at all between ma252 and ma352 when listening at lower volume. I rarely go above 45 on my 252. With 352 and same speakers, is ma352 going to be louder than ma252 at the same volume setting - or how would one describe the difference 252 vs 352 in this scenario 

The 352 and 353 do not sound quite the same at any volume. The 2 is more tuby sounding, were as the 3 is more neutral.