I posted this on the Naim community forum. There's been a very conspicuous silence. So yes, not as good as I initially thought. On the post before I said after my first listen that I felt like a teenager waiting for a second date when the first date had gone quite well.
So I had that second date with the Nait 5si and I’m sorry to say that it didn’t go so well. Neither did subsequent dates and we’ve decided to go our separate ways (ok, I think I’ve taken this date analogy far enough).
Anyway, this is what I found. This amplifier is fast and yes, I did get the PRaT thing that people go on about but my system wasn’t lacking rhythmic agility in the first place. I have an excellent digital front end with the ifi Zen One signature DAC with the ifi iPower X power supply and together with my Triangle Titus EZ bookshelf speakers I have focus, pacing and responsiveness in abundance. With the 5si there’s even more ability to stop/start on a dime, the Roberta Flack track Compared to What is a good example where things sounded faster, but I was kind of left thinking it was fast enough in the first place. What I don’t get is the sustain in notes that the Denon gives me, nor the roundness and sweetness in tone. I had to check this several times as it’s nearly £1500 vs £549 and I couldn’t believe what I was hearing. The British Audiophile talks about how this amplifier doesn’t give a full decay to transients and this is what I was definitely hearing. In the end the sound just lacks a bit of presence, certainly this is noticeable with vocals and then with plenty of instruments also. On Nouvelle Vague’s cover of Making plans for Nigel there’s all sorts percussive elements that sound much more satisfying on the Denon, the triangle sound just goes on for miles (and here I mean the percussion instrument not the speakers) while it’s just lost on the Nait 5si.
Don’t get me wrong, I think it’s a good amplifier but not in my system and to my ears and certainly not at nearly 3x the price at full rrp to my little Denon.