Power amplifiers with selector Class of operation?

This is typically a feature that allows amplifiers which are designed for a high bias current (i.e., mostly Class A amplifiers) to be run at a lower bias, as an energy saving feature.  The low bias setting typically decreases the power consumption and heat output, with the penalty being a decreased output in Class A (before switching to Class AB to provide the rated total power output), and some associated level of sonic degradation (i.e., increased distortion).  In addition to the amplifiers mentioned, some (but not all) Clayton Class A amplifiers include high/low bias switches.  

Speaker switching is not harmful to an amplifier and is a nice feature to have when using two pairs of speakers.

Have made our Olympia Series of amplifiers with a Low Bias / High Bias switch for years.  https://pbnaudio.com/eb-sa-amplifiers/

Good Listening

Peter

roberjerman, whether you think so, or not, speaker switching, brings the speaker output wiring, to the front, and then, back, to the rear of the amplifier, and, this, limits current, affects damping, and can only add / pick up noise. In your very large museum of power amplifiers, name me one American made power amplifier, that offers speaker switching. Bel, GAS, or whatever. When Adcom decided to eliminate the speaker switching, from the GFA 535, to the series II, this was an enormous upgrade ( other things, positive, changed, as well ). I can only imagine a Krell, Threshold or Levinson power amp ( of which I have owned many ) having speaker switching. Just use a 2nd amp, for a 2nd pair of speakers, or, change the speaker cables, manually, to the other pair. I find many statements of yours, ridiculous. But hey, we all have our opinions....Enjoy ! MrD.