I bought the 5i because I was looking to put together a small system for a house I rented in CO for a year. I was curious to see how good an integrated in this price range would sound, given some of the positive comments I was hearing. If you don't have a lot of experience with passives, the main reason people use them is because its very difficult to get a good sounding active line stage for a low price. Many people feel that is you can't get a good active preamp, use a passive or a source with a volume control instead. Needless to say, I'm one of those people. I should also mention that I'm very sensitive to high frequencies, so some of the things that bothered me about the 5i, may not bother you.
The best way that I can describe the overall sound of the Naim is that its not clean sounding. (There was nothing wrong with it. I was able put it next to another one in a store and the sound was identical.) When I first tried it with a pair of B&W LM-1's I had on my PC, the Naim sounded fine. But the B&W was a fairly dull sounding speaker with not too much detail. I needed a real pair of speakers, so I went out and bought a pair of Vandersteen 1's. When I put the Naim on those, it just fell apart. It's true that the Vandersteen is much more detailed and resolving, but its easy to drive and I don't think it was unfair to the Naim to pair it with that speaker. Naim said either the 1's or 2's would be OK.
What let me to believe that the Naim had a passive line stage, was the high frequencies. They weren't refined at all, as well as an overall harshness. It just sounded like a typical, cheap active line stage. I also had 2 other amps I bought to try; a Creek 5350SE and a Musical Fidelity A3.5. The MF was a bit cleaner sounding overall, and had a lot more power, but the highs sounded, more or less, like the Naim. The line stage in the MF I know is definitely active. The real test was when I put it next to the Creek. The 5350 does have a passive LS. When I put that in the system, there was an immediate difference. The highs were completely relaxed, but had more detail. There was no question that I was listening to a much better quality active preamp, or a passive. The difference was not at all subtle.
I should also point out, prior to my time with the Naim, I had quite a bit of experience using passives, so the Naim wasn't really a learning experience for me. I kind of know what to expect when I hear both designs. Not only that, don't read too much into what I'm saying here. You have the Naim and are getting excellent results. That's all that matters. It wasn't the right amp for me, but it definitely is the right amp for you. Don't let me, or anyone else, talk you out of enjoying your system.
