I’ve just found the spec sheet for the amp.Technics SU-X911 about 30 years old.
was considering the Dali spector 2 speakers.Just set it up after years stored away and want better sound speakers for small room.The Dali has excellent reviews
I see the amp has the (less than ideal) springclip speaker terminals - just means you're limited to thinner type bare wire cable (or 2 to 4mm adaptor plugs), no real problem.
Dali do quote 6 ohm nominal, which is just a more realistic rating for what others might describe as an 8 ohm speaker.
(Impedance is not fixed once the music hits).
You can't go wrong by following the golden rule; Keep volume level set for clean sound. Any audible distortion means amp and / or speakers (and ears) are suffering.