When I first got my MB-450s, I played around with it. I managed to make it a difficult lean to get around to the back of them so I have since usually switched only once every couple of months - usually when I'm listening to large scale symphonic works or opera. The rest of the time it stayed on triode.
Recently I got a pair of MUCH more efficient speakers so have no use for the added "stomp" that tetrode provides.
FWIW, I agree that piano and almost all single instrument classical or chamber music, jazz, and vocal is better done on triode. Tetrode really shines with music with "impulse" dynamics - things like Holst's Planets, Beethoven's Fifth, above-mentioned Mahler symphonies, and good feisty operas (Carmina Burana, Don Giovanni, etc).
Recently I got a pair of MUCH more efficient speakers so have no use for the added "stomp" that tetrode provides.
FWIW, I agree that piano and almost all single instrument classical or chamber music, jazz, and vocal is better done on triode. Tetrode really shines with music with "impulse" dynamics - things like Holst's Planets, Beethoven's Fifth, above-mentioned Mahler symphonies, and good feisty operas (Carmina Burana, Don Giovanni, etc).