Along with the amp, he gave me a pair of early 1970s 15 ohm Rogers LS3/5As. Which taps should be used for these speakers? I know nothing about tubes and don't want to damage the amp or speakers.
8 ohm. (It is closer to 15 ohms.)
Also, I have Harbeth speakers rated at 6 ohm. Does it matter which taps to use for these?
I would try both taps, there should not be a lot of difference, but sometimes one has more punch than the other.