Either your ears are clogged, or, the PA-7 you listened to was malfunctioning. It's the same as a Threshold Stasis, so that means you are trashing a Nelson Pass design??? ( I think not). Try passing off your opinion on DIY audio, and expect them to eat your lunch.
Listen to a PA-7 restored, and one will get some of the best sound from solid state available. The Lux is a fine receiver (I've owned one), but the power supply and drive characteristics from the Lux is nowhere near the Nakamichi. You are the only one I've read on the various threads who trashes the Nak. The Lux would have difficulty with a speaker like a Legacy or Kappa.
As the Brits say, it's horses for courses.