Since the 1980s, I’ve asked every loudspeaker designer I meet, “Which amplifier do you recommend you use with your loudspeakers?” Annoyingly, they always say, “My speakers are easy to drive. Any amp will do.” Whereupon I complained, “Aww, come on man, don’t feed me this. What amp did you use when you designed the speaker?” The manufacturer who came closest to a real answer was Wendell Diller of Magnepan, who, when I reviewed his 0.7 quasi-ribbon loudspeaker, said, “We used an amp of our own design. It’s not for sale. But any amp that doubles its power into 4 ohms will be fine.” Wendell’s answer helped me choose effective amplification…