So I’ve spent a bit of time today really getting down and ABing this amp with the 887 for over an hour and it’s pretty close honestly. The 887 might actually be a bit better overall than the SMSL SP200. I agree with Zeos that it’s a ‘hard sell’ overall. The 887 has more power, a better design (gain switch, not stupidly bright LED, RCA passthru) etc… and $100 less, and in some recordings it gets really close where it gets pretty hard to hear the advantages of the RNHP.
RNHP has a better volume indicator though… and a nicer feeling knob.
This testing did cement for me that there is definitely no advantage to balanced input or outputs on the 887 aside from more power. Sound quality might actually worsen marginally from the XLR balanced input… as I actually felt the results were closer when I used RCA on the 887 and xlr on the RNHP… as opposed to vise-versa.. or doing balanced input on both. I think the RNHP probably handles the 4 volt load better with it’s more carefully calibrated input impedance. It’s very marginal though and might not really matter. Could potentially be Placebo.
So what are the sound differences? I think it mainly comes down to the difference in dynamics. If I’m honest, it’s not super obvious all the time, even A/Bing it back and forth, but other times it was pretty definitive. There are certain songs you’ll hear some great dynamic range on the RNHP, but then switching to the THX, you’ll lose it by a small, but noticeable margin.
I’d say a couple notches above “Definitely NOT Placebo”.
Turning up the volume on the THX does not fix it either.. as I could push the THX to obviously louder volumes, but still get noticeably better dynamics on the RNHP. And I did all kinds of combinations to give the THX amp any sort of advantage.. giving it both balanced inputs and outputs.. etc. But again, have to stress I am talking about single-digit percentage differences.
In Z’s review he said… “It would be lame to say it (RNHP) sounds more musical…” and stopped short of REALLY declaring anything. And I understand the hesitation, but that is really an apt way to put it IMO. It takes a bit of the sterile, clean-nature of the THX sound and it sounds a touch more lively and not quite as ‘thin’.
It could very well be the RNHP has a touch hair of harmonic distortion that I’m not consciously hearing… or it could be as simple as the incredibly low output impedance letting the headphones produce an ever so slightly more transparent sound.
It could also be the nature of the ‘feed-forward error correction’ approach of the THX versus a more-straight forward clean-circuit design. Or maybe differences in the Op-Amp designs.
I honestly have no idea… They do sound very close in most instances, but the RNHP definitely edges out the THX. There was never a moment the THX sounded better than the RNHP and I’m certain the differences are regular and noticeable enough I could blind test and pick out the RNHP versus the 887 at least 9 out of 10 times… if not 10 out of 10.
My overall conclusion is that if you have the THX amps.. especially the 789 or 887 then you are fine for the most part. I’m still going to stick with the RNHP because it still resolves slightly better, especially with the Clears. I would actually recommend sticking with the RCA inputs on the THX amps and not bother with the XLR unless you really have a reason to do so… REALLY need the extra volume gain.. etc… which you really shouldn’t. The XLR gets converted to single-ended before it hits the amping circuit anyway.
That is my final take on this for now. =)
