If you want best for headphones l would look elsewhere than Naim. It’s not their strong point from my experience and they don’t output high enough for demanding headsets, many on here look to use dedicated headamps/dacs from other vendors. The Violectric range are highly regarded and many users on here have gone for them feeding from their streamers or preamps but many others available, some prefer the Chord solutions, I use RME for mine.
As a huge fan and longtime user of the V1 I would say look elsewhere for HP use. It’s fine for casual listening on headphones but that’s about it. The V1’s strongest point is its USB input, and the combo of DAC and preamp, so if not using those then you can do better elsewhere.
if this question is still relevant, the short answer is no. Not only is not noticeably better, but quite the opposite, it is inferior to me. I own both V1 and SN2 and my preference goes to SN2 HP Output; they are different to be politically correct, V1 is more conventional so to say, it is more balanced, goes a bit deeper as far as low freq are concerned, has a bigger body. On the other hand, SN2 is faster, midrange is clearer, with V1 you get more politeness, SN2 has more attack, it is bolder. I have tested both with my Senn HD660S if that’s a factor. Hope this helps
I used a Headline with a HiCap DR and it was pretty decent. I was more than happy at the time and it have me the Naim sound I love. It is not the last word in detail but it certainly entertains! I would look at a used HiCap even non DR of you want to stick with Naim. Its a great headphone amp, maybe not as good as other options but if buying used I suspect you could get the combo for about £600 ish plus you need a cable to power the HL do maybe another £40ish. Add about £350 more for a DR HiCap. The good thing here is that the combo will lose zero value now so use it and upgrade later on if you feel the need.
Third party power supplies are banned here for a good reason. Naims voicing is intrinsically linked to the power supplies. Just buy a used Naim one if you want to save some money. Naim has designed a system that works fantastically and is voiced as a whole. I am sorry but in my opinion no power supply other than Naim will give the true Naim sound as intended. If you start messing with the Naim sound then you might as well buy a different brand altogether. Its not like the headline is top of the tree anyway!