They are balanced, yes, but there’s virtually no difference on the SP200, as both the 1/4" and the XLR outputs have the same output stage with 6 watts per channel @ 16 ohms and the amp itself isn’t fully balanced anyway. I’ll give it a more thorough listen for sure, using both connectors, but as I see it the XLR output is just a convenience output for users already having a balanced cable.
1 Like
Another little update from me now. After listening for the past 4 hours on all three headphones (Amiron Home, Sundara, Argon MK3) I found a few other things pretty interesting:
-
The channel separation is ever so slightly, but still noticeably, better on the SP200. I often had to check the wave form of both channels because I thought I was hearing channel imbalance on the SP200, but not the case with my unit, it’s just one channel being ever so slightly louder than the other. I wasn’t able to notice those very small differences in channel loudness with the Atom amp.
Here you can see the right channel being ever so slightly louder. This subtle deviation isn’t nearly as obviously audible on the Atom as on the SP200. -
Coming back to very insensitive / power hungry headphones (a.k.a. the Argons): Yes, they indeed sound better on more power. I couldn’t hear any audible difference between the XLR and the 1/4" output on the SP200, which isn’t very surprising considering how it’s built internally (both using the same output stage). As described earlier already they sound ever so slightly fuller and round on the SP200 compared to the Atom and the bass is literally worlds better. It’s such an obvious difference that every random stranger on the street could tell as much. It’s that much better.
-
Surprisingly, female vocals if mixed with many instruments sound slightly clearer on the Atom amp. I can’t exactly tell why. Has anyone maybe got an idea as to why this is? For instance on the chorus of Someone like you by Adele the Atom actually is able to reproduce Adele’s voice slightly clearer, whereas on the SP200 her voice starts to scratch and isn’t as smooth. This effect is very noticeable on the Amiron Homes, not so much on the Argons and almost completely fades away on the Sundaras.
This leaves me with the initial point I made: Is it worth upgrading to the SP200 (or any THX amp for that matter) if you already have an extremely clean sounding solid state amp like the JDS Labs Atom (or the like)? Is the final 3%-5% jump in sound quality worth it to pay 200$ on top?
I can’t answer this unfortunately and am still not certain if I want to send my unit back or keep it. It’s pretty much state of the art and if you’re searching for the best and flat solid state sound currently available on the market without having to sell your organs on the black market to be able to afford something like a Benchmark HPA4 then I think it’s absolutely worth it to go spend the 300$ on it and “be done” (on the solid state amplification side of things).
I still have to find an answer to that myself. What would you do?
Thanks for reading!
4 Likes
I mean honestly I just want a clean SS for (Filthy Acts at) a Reasonable Price so right now I’m between the Archel Pro 2.5 and now getting curious for the SMSL SP200, since they both seem to be good for SS, one has more power and the other has less distortion but the difference atm is Price range, so idk, I wish had the 2.5 to get an idea.
Also about the Atom vs SP200 on Female Vocals, maybe Output Impedance has something to do with it? I mean the impedances are super low tho so idk how that could actually affect it (I think they both have around just 1 ohm), or maybe power output being more current than voltage heavy or vice versa, or internal inductance at some point, idk tbh. Still great read and while the HPA4 gets me excited, idk how much of a step up it is vs Other SS THX offerings. Idk, maybe it’s better sounding but idk how much of a difference there could be.
The Internals tho of the HPA4 are pretty damn sexy (in a Big PCB-ridden type of way), especially the Motorized Potentiometer.
Getting the Archel 2 pro in a couple of days. Have the original archel pro. Will update if it’s better than its predecessor. Whatever said and done their service is freaking amazing.
1 Like
I don’t have the sp200 nor the atom. But using my thx789 and liquid spark, I hear the same difference. With th LS vocals sound clearer and thick on the thx789 they sound a little haze. I did notice more sound on one side or it became more apparent with the thx789.
1 Like
Very interesting.
I tested this further now and found a perfect example, not with vocals but with flutes. In the Your Name soundtrack 三葉の通学 (Mitsuha no tsuugaku), this is painfully audible on all three headphones I currently test on.
For record the source is lossless 16 bit at a sample rate of 44100 Hz, so standard CD quality.
On the Atom amp, the flutes sound exactly as you’d expect. Super smooth and rich with barely any texture, if any to begin with. On the SP200 it almost sounds like a Cello playing with so much texture that it actually sounds like a completely different instrument that’s somehow broken.
Output impedance can be ruled out as both are very close to 1 ohm.
Has anyone got an idea? Testing those two amps this is literally the only thing that’s leaving me behind completely baffled.
@M0N with the incredible amount of gear you have heared and tested so far, do you maybe have any clue as to what this could cause? Not only because it’s just me but also @Alfredo3001 experiencing this with their THX amp.
1 Like
I’m pretty sure that’s because of the topology of the thx compared to other amps. Feed-forward has it’s limitations compared to other designs
Actually makes a lot of sense, thanks for the answer! I just wonder how come nobody really seems to address this in their reviews? Why is nobody really bitching about this online?
That’s a pretty apparent and very audible issue with THX tech in my opinion then.
1 Like
Personally I have mentioned on here that thx are definitely not end game amps, and with headphones in the 1k range and above they kinda fall apart and show their flaws. Personally if I wanted a neutral and accurate amp in the thx price range, the rupert neve rnhp is where it’s at 
For most people thx is all they need, and if they don’t cross the like 800 and above or get picky headphones most people can’t complain. It’s easy to recommend a thx amp for most people, but with higher end stuff I would really just suggest looking into better amps imo
Also a decent amount of people can’t pick that out either, hearing is a skill that you have to develop with experience and learning (so good job lol)
2 Likes
That’s very interesting to hear, thanks a lot for your insight on all that, really appreciate it a lot 
What would you say is your end game amp if you were looking for clarity and a neutral sound (price range 1k - ???) ?
Anything from benchmark
Isn’t their flagship the HPA4 which also happens to use THX feed forwarding tech? Or do they also have other amps with a very flat frequency response?
Well, I mean 1st there is no end game lol, and 2nd if you want to see what I have currently, you can check my profile. There are lots and lots of options from 1k and beyond, so I think it would really come down to preferences there.
1 Like
Hate the term neutral and accurate. It implies a correctness that I don’t think it embodies.
THX didn’t invent feed forwards it’s been around since the 80’s at least and probably before that.
All amp designs have tradeoffs, companies like PS Audio build 0 feedback designs, which are generally considered to be better sounding, but will never have good measurements.
Designs like the THX have a ton of feedback, and hence better measurements, but feedback is generally considered a bad thing for the sound in amp design.
FWIW the only THX amp I’ve heard the 789 is a good sounding SS amp, but it’s certainly not as good as some of the higher end stuff.
1 Like
TBH I would rate some other similarly priced headphone amps better than the benchmark to me, but the benchmark is a step up even though it is still thx
1 Like
Well I mean I would say the rnhp is more correct sounding (being closer to life) than the thx stuff, but yeah it is a pretty extreme term
Also yes the topology is nothing new, it was just re popularized by thx recently
1 Like
I hate it because you can have a dozen amps that all have flat frequency sweeps, and all sound different to each other, and it ends up being applied to the dryest, least interesting sounding one. Then people seem to think it’s a positive description…
2 Likes
Lol, very true. Something neutral and accurate to me is something that is closes to life and the most accurate to a real representation.
Personally what you describe is what I would call analytical lol
2 Likes
Thanks a lot to both of you! I’ve learnt quite a bit about all this today. The only thing that really baffles me is that the THX stuff is so incredibly overhyped online and stated as the only SS amp you’ll ever need / want when in reality there is issues and limits with this tech. Not even picky reviewers like the guys from AudioScienceReview have pointed something like that out (even in the slightest). Maybe I’m also just cursed with being able to hear those subtleties 
Oh god ASR lol. I don’t think I want to bring up that discussion lol