This amp is part of an upgrade I did for my iMac's sound. I went from and integrated DAC and amplifier and inexpensive Sony headphones to a separate DAC, this amp and Audeze headphones. Overall I'm very pleased with the performance of all my new components. And the price is right! This amp provides more than enough power for my new headphones and really seems to have a nice, flat frequency response. I like nice tight bass without any boominess and this amp and headphone combination gives me the sound I like. Nice smooth volume control and the gain switch gives you some adjustment to account for the power your headphones need, or to just change the sensitivity of the volume knob. I'm using this with the single ended inputs and outputs which is probably fine since my understanding is that the amplification circuitry is single ended. Obviously anything I really say about this amp is also related to my end to end system including the DAC and headphones. But I have no complaints whatsoever. I can listen to my new system for hours without any sort of listener fatigue. Overall a very nice headphone amp that I am extremely happy with.

It has been two months since I began using this amplifier and I have to say kudos to S.M.S.L. for producing a headphone amp strong and reliable enough to drive my HiFiMan Arya headphones. Now before buying this amp, I had blown through four"”yes four"”failed headphone amplifiers: two Topping A90s and two Monolith THX 887 amps (see my reviews at their respective Amazon product pages for details). So when I decided to buy this amp, my expectation of reliability was a bit low, to put it mildly, which is why I wanted to wait a while before posting a review just in case.

So how does it compare to the Topping A90? Well, I will continue to maintain that the Topping A90 is still the best headphone amp I have ever heard. This does not quite match it in clarity of detail. However, that's totally irrelevant having bought and returned two failed units in a two-month time span. I'm no longer willing to gamble my hard-earned money on amps produced by that company no matter how highly rated, at least not until they fix their quality control issues.

And as compared to the Monolith 887 by Monoprice, quite frankly I can't tell a lick of difference in sound quality between the 887 and this amp. In fact, I much prefer the SP 200 because of its smaller form factor coupled with its integrated power supply. Yes, the Monolith does have three gain settings as opposed to the two in this unit which might make running IEMs an issue for some. But if like me, you use your DAC to control volume this shouldn't be much of a concern. And when it comes to reliability, well it obviously beats the Monolith and for less money! What's not to love?

Quite frankly, for this price, this is an absolutely killer headphone amp. At 6 watts output, it effortlessly drives my Aryas in either balanced or single-ended mode. So a tip of my hat to S.M.S.L. for not only manufacturing a great-sounding desktop amp with a ridiculously small footprint but for caring enough about their customers to institute quality control procedures sorely lacking at both Topping and Monoprice.

The hype regarding the THX chipset is definitely real, however, and I have verified this with the THX 789 chipset containing Monoprice Monolith portable, a significant break in is required for THX chipset containing headphone amps in order for them to sound their best. Out of the box the SP200's high end is overly aggressive and fatiguing, even painfully so. But after 20 or so hours of break/burn in, the high end mellowed significantly and suddenly became one of the most accurate and detailed headphone amps I've ever heard. To be clear, this amp is not warm, or organic sounding. Rather it is almost brutal in terms of its accuracy and detail. If the music is poorly engineered, the SP200 will convey that poor recording quality, but if you listen to music that is engineered well, the SP200 is spectacular.

I'm listening to my SP200 connected via XLR to an SMSL M500 DAC, with music from Tidal via USB to the M500, and on a variety of headphones and IEMs, including the Sennheiser HD660s, Tin HiFi T2s, and TRN V90s via the SP200's balanced output, the experience is pretty consistent between the different headphones and IEMs. Out of the box, and I do want to stress this, the SP200 is almost un-listenable, but after 20 or so hours of break/burn in, it transforms into something rather remarkable and spectacular and definitely worth the hype given to THX chipset containing headphone amps. So upon receiving and un-boxing your SP200, plan on plugging it in, connecting it to a source and a pair of headphones or IEMs and setting it to a moderate but listenable volume level, then leave it to play your favorite music on repeat, overnight, for 2-3 nights in a row to let it break/burn in. Then start listening to it after its break/burn in is complete, otherwise you will be disappointed in how its high end sounds, and even consider selling/returning it. But just give it some time and it will mellow and become the amazing and awesomely accurate and detailed amp that everyone is raving about.

This is not just an amp mind you, its THX certified, and can pump 6-whopping watts into 16-OHMS, or 3-whopping watts into 32-OHMS. This is probably the most powerful headphone amp that you can buy for the money, especially having THX. But what is great, even if you have unbalanced headphones, like the V-Moda's, there is a 1/4 unbalanced headphone connection on the front for those. There is also a unbalanced XLR connection on the front as well.

On the rear of the amp, are both unbalanced left and right channel XLR inputs, as well as unbalanced RCA inputs. It comes with an on/off switch, input selector switch, and low/high gain switch, as well as the volume control. Because I am going with this setup, I'm bypassing my speaker system all together. I'm using a Monoprice RCA premium 22-gauge cable, to literally connect from the output of my Realistic EQ box, directly into the headphone amp.

And its so nice that the V-Moda's come with their own 1/8 to 1/4 adapter, cause I needed that to plug into the new amp. I know I am not the only one who got fooled into thinking the XLR connections were balanced, based off reading the description of the product. But like many of us, we eventually learn the truth. The XLR connections are not balanced. Not that big of a deal per say, they work perfectly fine, and offer convenience of connection if you do have XLR.

When I first tried the amp on low gain, I felt it was too quiet, at all levels up to 50% volume. My V-Moda LP2's are 32 OHM headphones, and I think they just need the full 3-watts, so I flipped the GAIN switch to HIGH POWER! All the sudden my can's woke up, and now when the volume is set to 50%, my cans get real loud! I tested the cans with the typical bass track I always use, Wiz Khalifa On My Level - BASS BOOSTED, and holy molly! I also listened to Jelly Role - Creature, Feel That Bass III, and Post Malone - Go Flex. They all sounded amazing with the amp at 50%.

The bass hits are punchy, and they get down low. This amp seems to like straight up amplification with noise floor reduction. I find that it doesn't seem to mess with the frequencies at all, and if anything, sound is more analytical and amplified. I really like how this amp does its job, I feel like I can hear everything in the tracks, even stuff I never heard before. The amp really brings both the music, and the headphones to life. The THX portion of the amp seems to provide for a very clean sound.

Most of the time, I can keep the volume at the 10 O clock position for general listening. Or if I want to listen to something loud, I push it to 50%. Other then songs, I tested this amp while gaming. If you thought your headphones sounded good before. Well, I am here to tell you, once you plug a pair of can's into this amp, your gaming world will be amazingly enhanced like it was not before. That means you can hear things more, and feel things, with a solid pair of 50mm drivers or better.

Overall, I am extremely pleased with this amp, it does exactly what I need it to do, bring headphones to life, that is what this amp excels at. I am aware that some people got defective boxes in the past, thankfully, mine was not defective. Nor did I have that strange volume issue that someone else had, where only the left channel was heard, until the volume was at 50%, my volume works perfectly fine. Also, some people complained about the POWER LED being super bright, blindingly like a flashlight. Mine is nothing like that, just a dim blue glow, so I think they fixed that.

Now while my volume potentiometer, or POT for short, may work properly in the technical sense, in the physical sense, its practically awful. If you've experienced a smooth moving volume knob before, well this volume knob is kind of rough. Multiple reviews cover on this fact as well, so don't just take my word for it. Because of it, I went on a competitor website and ordered a golden aluminum 25mm volume knob as replacement. With the added weight of a metal knob, should smoothen out the POT movement.

Do I recommend this amp? Absolutely! I used to use those portable Fiio amps, they are not even in the same weight class, as the S.M.S.L desktop amp. But you might want to think about replacing the volume knob is all. Other then that, and the fact its not really a balanced amp, its a perfect little unit. 5 out of 5 stars!

I got the amp because I wanted more power for my Modhouse Argon MkII to bring out their best.

The amp DOES do what I wanted. Much better performance than I was getting from my Drop Cavalli LCX + SDAC.

Problems:
* There is a right-side balance bias that skews the soundscape, throwing off instrument and voice placement in the soundstage
* There is also a right side volume imbalance. Expected in analog potentiometers, but it's pretty severe up until between about 8-9 o'clock on the dial. I could overlook up to 6 or 7 o'clock.

These 2 issues make an otherwise stellar performance always just shy of 100% satisfying when actively listening or auditioning headphones and especially iems. Super sensitive iems might never need to go beyond 9 o'clock even on low power setting, so the pot imbalance is always there.

For headphones, things get better. The volume imbalance stops being a major issue, but the soundstage skewing is sometimes distracting. Definitely prevents me from counting this as a "reference amp", which is disappointing because it performs SO well in most other ways.