I have a couple of the Nak PA-7 amplifiers along with the matching CA5 preamp in my collection. They are well-designed, and nice sounding amps when new. Mine sound very nice and not overly detailed but actually a little rolled off in the highs. They are not performing at their best due to them needing to be serviced and brought back up to spec. I intend to rebuild them both and upgrade the input section according to the recommendation on DIY audio. Be advised that any amplifier as old as the PA7s are will need to be serviced to sound their best (complete recap, replace the bias pots, etc.). The PA7 has very large power capacitors that are now difficult to source and very expensive.
Unless you are wanting to stay with vintage gear (nothing wrong with that at all) you might want to consider the Galion TS-A75 amplifier. I am blown away with the build quality and the sound for the price. Not sure what kind of power your speakers need, but I have not even come close to needing all 75 watts/ch driving a set of Thiel CS3.5s on one of my vintage systems. Lots of soundstage depth and width. Instrument placement outstanding. No harshness on bright passages or female vocals (unless it is recorded badly). I like mine so much, I purchased the new 25watt/ch Galion TS=A20. It has lower gain,so it takes some getting used to, but the sound is amazing.
Not sure if I helped any, but good luck with your decision.