Massdrop + THX AAA 789 Headphone Amp Reviews Compendium

Compendium updated January 22nd, 2021.

Ask any audio reviewer worth their salt, and they’ll tell you that we’ve entered the age of the giant slayer. It seems that on every blog and youtube channel, mid-tier Davids are being pitted against hi-fi Goliaths and coming out ahead. There’s probably never been a better time in this hobby for the budget-conscious, so grab your popcorn, dive into some reviews, and watch the Massdrop + THX AAA-789 slay slay slay. 

We’ve compiled reviews from across the web for your reference. What you’ll find here are the TLDR versions of the full reviews (which you can access with the provided links). We’ll continue updating this compendium as reviews come in. 


From Audio Science Review's review of the Massdrop + THX AAA 789 Headphone Amplifier, first published on October 28th, 2018:

Wow! That is stunning. We are getting SINAD (signal above distortion and noise) of 117 dB. That beats the best DAC we have ever measured (115 dB SINAD). It by far shatters all previous records.

“As expected we get a ton more power at 1.3 watts. Performance remains impeccable with both channels exactly on top of each other producing astonishingly small distortion and noise at that power level. Quite remarkable...

“Frequency response is essentially ruler flat to 40 kHz:

“It takes a lot for someone like me who likes finding faults to smile ear to ear in testing audio gear. But that is exactly what THX and Massdrop have achieved. With a SIAND that matches the best dynamic range of our hearing system, you are assured that the only distortion you hear is either in the source or your headphones. Not only that, but we also have tons of power to drive any headphone at a price that is hard to believe for this level of performance.

So let me make this short: the Massdrop THX AAA 789 has my strongest recommendation. Buy one and be happy forever.

From Headfonia's review of the Massdrop + THX AAA 789 Headphone Amplifier, first published on November 11th, 2019: 

“So is it “a wire with a gain”? In some ways, you can call it that way. The background is dead silent with over-ear headphones (but not with super sensitive IEMs like the Campfire Andromeda Gold). There is a preciseness and cleanliness to the sound. Bass beats can seem almost edgy and have good impact with no bloatiness or fuzziness. It to me feels like it’s easy to separate instruments with these sound qualities. I think this works out extremely well with electronic music.

“I’ve listened to many tube headphone amplifiers and I’ve definitely felt that there’s a sense of space in the sound. It’s probably harmonic distortion and warmth from the tubes, but it works for me. That sense of space is missing with the THX 789 however. Moreover, so is any other type of coloration. It’s a neutral sounding amp…

The Drop (former Massdrop) THX 789 is a wonderful headphone amplifier. Displaying a clean and precise sound signature with a black background and plenty of punch is not an easy achievement, but… at some point I know I’ll start to look for some type of coloration… Call it a flavor to the sound. But at the moment, I’m liking this flavor of preciseness.”


From Ruben Orduz' review of the Massdrop + THX AAA 789 Headphone Amplifier, first published on November 16th, 2018:

“Conclusion: if you can only afford one mid-range headphone amplifier, no question in my mind the THX AAA 789 should at the top of your shopping list. That having been said, if this will be your second or third amp and you have a penchant for a particular sound and tonality or the grit and warmth of vacuum tube amps are your thing, you might find yourself conflicted: on the one hand enjoying the likely quietest (highest SNR) of any amp $500 or less — actually I’d say you’d have a really hard time finding a better amp for less than $1000 right now — but on the other it’s so neutral and transparent that it might feel gutless and soulless. Whatever the case, both Massdrop and THX have hit a grand slam with this best-in-class headphone amplifier and would wholeheartedly recommend it.”


From Darko Audio's review of the Massdrop + THX AAA 789 Headphone Amplifier, first published on August 13th, 2020:

“The Drop + THX AAA 789 has a lot going for it. The enclosure is quite attractive if perhaps a bit utilitarian. Functionality is excellent, with the robust connectivity plus three-stage gain selection that, at last (!), gives us more headroom with sensitive IEMs. It’s powerful enough to drive anything and seems to pair best with significantly more expensive headphones – a sure sign of this amplifier transcending the “budget” category. Listeners chasing enhanced bass impact, a creamy midrange or some other fun coloration might find the 789 somewhat arresting but those seeking the limits of brutal honesty will be handsomely rewarded.”


From Soundnews' review of the Massdrop + THX AAA 789 Headphone Amplifier, first published on November 22nd, 2019:

Massdrop THX-789 sounded almost as detailed and as transparent as HPA4. The only area where I felt it loses - is the frequency response, especially in the sub-bass area. It just doesn’t go to Mariana Trench levels as HPA4 does and doesn’t rumble my head as much when it is needed. Overall, it is gentler and smother sounding by comparison. Its spectral decay is longer and musical notes will linger a bit more. You might like this kind of approach with jazz or classical music. The background I would say it is just a hint greyer and not as black. Transient response is good but not the best, it is the slower sounding unit compared to the rest. I felt that its power output is lower compared to the rest and as a result this is probably why I didn’t hear the fastest transients or the best diaphragm control. Soundstage size also took a small hit and everything just happens closer to me, it is a bit harder focusing on everything in a crowded track and the air bubbles are smaller in size. All in all, this is a very good amp, it is pretty close to HPA4 once you volume match them, but still I would like to see few things improved in the future.


From Passion for Sound's review of the Massdrop + THX AAA 789 Headphone Amplifier, first published on December 10th, 2018:

“The 789 is way better than it deserves to be. This amplifier has shocked me. I have to admit that i bought it back in 2018, on a whim...and I am absolutely blown away with what I’m hearing. It’s incredibly detailed, incredibly transparent, and for the price it is just insane.

It has instantly become my second favorite amplifier of all time.” 


From Joshua Valour's review of the Massdrop + THX AAA 789 Headphone Amplifier, first published on December 20th, 2018: 

“I really could go days and days and days talking about this amplifier, but I think you get the point….it’s a hell of a deal. Even comparing it to a fully class A, fully balanced amplifier….I think it’s a more than competent amplifier.



Editor’s note: Emphases ours.