Which B&K ST-140?

The consensus on re/blue vs. gold is mixed. Most opinions I have heard favor the red/blue 105W for sound and ability to drive low impedance loads. Most opinions hold them as only subtly different sounding.
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1074209541&read&keyw&zzst-140+red+blue
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1163363785
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1201935167&read&keyw&zzst-140+red+blue

The B&K ST 140 is not the best choice for low impedance speakers.

http://www.stereophile.com/content/bk-st-140-power-amplifier-1989-measurements

Yspm,
Here's the best part of the link from your post:

"Here is a partial list of amps that have been bettered by the little B&K in my system. Aragon 2004, Hafler Transnova 9300, Meitner STR-50, Sumo Andromada, Counterpoint SA-12, Denon 2200, ASL 1003, and several others I don't recall at the moment."

Curious to know what else was used in those systems that made the B&K come out a winner, but still very impressive...

Unsound, revealing my ignorance, what is a low impedence speaker generally? I think most are 8 ohms, a few 4 I have heard of. Do you mean 4 ohm speakers? Why is the B&K not good for 4 ohm-ers?

Thanks....

River251, Speakers have minimal impedance and nominal impedance. One should know not only the impedance swing of a speaker, but also the phase angle before choosing amplification for a given speaker.
What is a low impedance? What is a high impedance? Well, I think that might be very subjective, and many here on Audiogon might have very differing opinions on both. IMHO, in the big picture 6-8 ohms is the middle ground, anything below 4 Ohms is low, and anything over 8 Ohms is high, but there are other important considerations, and speakers ultimately decide.