klipshorn speakers

I heard a big Mac solid state amp feeding high efficiency speakers and it was a terrible sounding combination.  At any reasonable listening level the sound was lifeless and unengaging.  With high efficiency speakers you don't need much power, you need something that delivers great sound at fractions of a watt output.  Look at low-powered tube amps, most of the best sounding amps I've heard have rated power output under 40 watts.  I don't think the tube Mac amp--275 is the answer either; I heard that in a high efficiency system and it was also pretty bad sounding (also lifeless).

I don't think you need 40 watts, but, the Synthesis A40 is a terrific sounding integrated amplifier (it includes a very good DAC) that would fit the bill.  

my son likes mcintosh! but will the sound be better with a mc602 is what i'm asking! 

No, it will not sound any better. The power advantage is meaningless as the MC7300 will easily drive the Khorns into utter distortion and burst both your son's ear drums. I think a Class A solid state amp would be the way to go. Anything more than 100 watts/ch  is a waste of money.

If your son is set on McIntosh I suggest he look for a properly refurbished MC225 (vintage tube power amp with approx. 25 watts/channel).

I've listened to it in 2 Khorn systems and it was a great match, though both systems used tube preamps as well.

DeKay

@larryi  Has it 100% right. Mac makes great looking gear but other brands make great sounding music.