Reciver/Integrated same sound?

That one could not tell the difference between a NAD receiver and a NAD integrated doesn't say a lot to me. Yes, I think NAD is seriously overrated. Slow, dark and veiled. Can't imagine how you could tell the difference between components unless we're distinguishing the difference between muddy and slightly less muddy.

Very rarely did receivers come close to the performance of integrated amps; they were made for different markets and to different standards. Two integrated amps from the same company were not guaranteed to sound the same; let alone an amp and a receiver.

Receiver can mean 2 channels with a tuner, or a multi channel SSP? Regardless, an integrated amp at the same price should outperform it, although it may not be obvious with all speakers. You'd expect a lot of the difference to show up in drive capability and that would be more apparent with difficult to drive speakers. A pretty common disagreement around these parts is whether a high end integrated can outperform separates - so they can certainly be made to very high performance levels.

In my experience, I know of only a handful of receivers over a 40-year period that were designed and built to audiophile standards. The only ones that come to mind are Tandberg (who shielded and isolated each section from the others), ADS, and McIntosh. But I can name a lot of integrateds that make serious sound and rival separates. Not only are there pricey ones from Krell, Pass, Pathos, Bryston, and the like, there are excellent affordable ones from Onkyo, Denon, Yamaha, Cambridge, Creek, Rega, Music Hall, Musical Fidelity, Rogue, Primaluna, all of which will trounce any receiver i can think of,

So in a sense, it doesn't matter whether you *could* get equivalent sound in a receiver, the historical reality is that almost no manufacturer tries to do so.