Can you rate these amps for me?

From the worst to best:

Old 2270 marantz receiver
2105 mcintosh amp
krell kav-300 amp
B&K ST-140 amp
I have owned all but the Marantz so I will leave that one out...
Least favorite B&K St 140... felt it was a bit flat and
bass was unrealistic

Second place Mcintosh... Had great power looked cool and was a solid performer with nice highs.

First Place Krell Kav 300 I tend to like Aragons sound and the Krell reminded me of my Aragon Palladiums..
there is something sexy about Krell and I like the powerful sound.

Associated gear...
Mirage M5si
Audio Research LS7 preamp
Rega P3 turntable
Classe CDP3
too many mods to list...

Happy listening!
Custom Audio LLC
p.s. we dont have any affiliation with the above
mentioned brands
The 2270 was the most popular of the well respected Marantz 22xx series of receivers from the 1970's, but it was also a bit of an anomaly. It had the characteristic warm, beefy sound of other Marantz receivers; but it operated a bit strangely with 4 ohm loads. The 2270 was rated at 70 wpc at 8 ohms; but was measured at only 46 wpc at 4 ohms ... the opposite of what you would expect. So, you would need to exercise some care with speaker matching.

The tuner section was pretty top notch, if that helps any. I use two vintage Marantz receivers (2216B & 2240) in my various set-ups. The sound of the 2240 comes closest to the sound of the 2270. The sound has good rhythm and pace to it, but it is not as detailed or refined as some other amps that I own (NAD 320BEE; Musical Fidelity A300).

Associated gear: Speakers: Acoustic Research 302; NAD SB2. CD players: Musical Fidelity CD PRE 24; SONY SCD 555 ES; Music Hall MMF CD 25. DVD players: SONY DV560; JVC SA602

Regards, Rich
I can only address the McIntosh vs. Krell.

Years ago I had two 2105's driving a double set of AR-LST's (Cello Amati's). I had this configuration for many, many years. I then bought the Krell KST-100 when it first came out. That one little amp blew away the pair of Mc's.

Hope this helps,