Many of these amps are single-ended, that is, they have one output signal referenced to ground. In such case, one cannot simply switch signal and ground to reverse polarity. The only way would be to add another stage which ain't the best way. Swapping the speaker leads does it better.
Question about polarity-inverting preamps
You will see that I am technically challenged...
Many tube preamps invert polarity. Why don't (or why can't) the designers simply reverse the leads at the out jacks to make the polarity correct? Then we wouldn't have to reverse them ourselves at the amplifier or speaker.
--dan
Many tube preamps invert polarity. Why don't (or why can't) the designers simply reverse the leads at the out jacks to make the polarity correct? Then we wouldn't have to reverse them ourselves at the amplifier or speaker.
--dan