Well Ive ran it from yesterday evening over night until today late afternoon when I got home from work. Playing music all that time but the sound is still pretty anaemic and dull. Not sure if if worth recapping at this point, I think its best I sell it and get another Yammie
Its kind of ironic that HD800 with the NAD aren't bright enough for me...not that the Yammie is bright but its very...sweet sounding with lots of energy. I do get slight hum with HD800 but its so slight and I can only hear when music is paused that it doesn't bother me at all, and even slightly microphonic tubes bother me for example. I initially found a lot of hum with HD800 but its because the loudness know was turned all the way up, hum is in the highest frequencies.
Im not sorry I got the NAD, I really wanted to hear how it sounds but it only confirms I am really into Yamaha's sound signature ever since I got a receiver about 12 years ago.
Yup 'anaemic and dul' are the last words I'd use to describe the typical vintage NAD... Especially the PE models with the extra power. But they do have lower impedance out than 70's amps in general and so from my experience the HD800 do sound more full with the typical 70's 120 ohms output.
Tonality aside, It was only after a lot of comparisons with the NAD's that I realised my Pioneer's and Sansui's were giving out a little too much bloom at the bottom end with the 300ohm Senn's. This can sound great with electronic music or rock but not great with classical (and 95% of my listening is this).
A typical NAD should sound balanced but with a very slight tilt to warmth over neutral. But I must stress that the treble shouldn't suffer any dullness or veil, but quite the opposite. Only there won't be any glare or extra light.
Anyways, shame you aren't happy with it bud and I feel partly responsible , but because of how you have described the sound it really must need some work
Just for the record, I've bought about 20 vintage amps now and only a quarter of them I've been very happy with... It's all part of the game and luck of the draw with these old machines. The outside of them may look great, but its the insides that matter..
Anyway's theres nothing wrong with Yammy's! I had one for a short while and it sounded super!
Good luck next time and I do hope you keep up the vintage journey as it can be great fun and very rewarding. :)