Integrated Amplifier for Monitor Audio Silver S2 Speakers

viridian +2

@djengan, in your budget I would also check out the Arcam FMJ 39 and the Parsound Halo Int. Good luck with your search.

Cheers,

Scott

A Sugden A21 should give you everything you want and sound better than most solid state. I was really impressed. 

Get yourself a Parasound Halo Integrated.  It has plenty of power, has a great built in dac, has tone controls, 160wpc, phono input, balanced inputs and outputs and sounds wonderful.  I replaced a Rogue Cronus Magnum Integrated with this and couldn't be happier.

Hi djengan, 
I'm in agreement with Viridian,  amplifiers do make a significant difference.  You've already proven this fact with the Accuphase amplifier placed in your system,  clearly superior sound to the NAD.  Electronics make a considerable impact.  It isn't just about the speakers,  yes they're important but tend to be over emphasized in my opinion. I've heard numerous examples where upgrading an amplifier resulted in significant sound quality. Can speakers do this? Of course,  but so can power amplifiers. 
Best Wishes, 
Charles 

Djengan,
Roxy54 who posted above has very good ears and taste IMO. The Sugden A21 SE he recommended is worthy of more scrutiny.  A solid state pure class A amplifier noted for really fine sound quality  (very organic and sophisticated). Built with exceptional parts quality. 
Charles