Ye they sound little diffrently everytime.Go to Naim forum,there is alot of discussion about Naim 250.And yes it could be used with another preamps.
Naim NAP 250
I know that the Naim Nap250 has been in production for a long time. I'm wondering if dependig on when the amp was made if there is a difference in sound? Are some years or versions better than others? Or are they all about the same. Is there anything in particular I should be looking for or any questions I should be asking when considering purchasing an older amp? I would also like to know if the Nap 250 can be used with non Naim preamps. I would be a Linn Majik as a pre until I could afford a Naim pre. Thanks.