The caps in that Nad are good 30 years old, generally the life of caps is about 15 years before they start to wear out and change the sound of a particular amp. The real character of this little beauty may not be what you are hearing so making a judgment after 30 years on the sound of the amp is kind of unfair.
In its day it was a great sounding amp and I had the pleasure of listening to one brand new bought by a very close friend who continued to own it for next decade or so driving his Wharfrdale Diamond initially and later the Wharfdale E40's. I had owned the Nad 3225PE which essentially was the same amp albeit with "Power Envelope" circuitry incorporated.
The Nad 3020A was the poor audiophiles integrated amp as I remember it being dubbed by the press.
Just my 0.02
In its day it was a great sounding amp and I had the pleasure of listening to one brand new bought by a very close friend who continued to own it for next decade or so driving his Wharfrdale Diamond initially and later the Wharfdale E40's. I had owned the Nad 3225PE which essentially was the same amp albeit with "Power Envelope" circuitry incorporated.
The Nad 3020A was the poor audiophiles integrated amp as I remember it being dubbed by the press.
Just my 0.02