Disclaimer: The AAA™ 789 was sent to me by Drop, they did not do anything to
influence my opinion. Huge thanks to Drop for the sample unit.
Introduction & Overview
Introduction:
"Announced at CES 2018, the Drop + THX Achromatic Audio Amplifier (THX
AAA™) 789 is a linear bipolar amplifier with feed-forward error
correction. It’s designed for objectivists who appreciate an incredibly
clean, transparent amp—the sought-after “wire with gain” whose
amplification is wholly uncolored by a sound of it's own. Made in
collaboration with THX Ltd., it features the company’s groundbreaking
THX AAA and feed-forward topology, which reduce distortion by 20 to 40
dB for realistic, fatigue-free listening. In fact, this bridged-output
amp’s performance figures speak for themselves: It’s powerful (2 x 6W at
32 ohms) and quiet (136 dB SNR) with a record-low THD of -140 dB at 300
ohms, 100 mW. That’s four times the power of the Objective 2 amp, for
example, with far less distortion."
The Paragraph above is the first paragraph on the Drop website talking about the AAA 789 and honestly it perfectly encapsulates what this product is and who it's for. Simply put it's a headphone amp for objectivists. Many of you reading this will know I lean to the subjectivist side of things, but part of the magic of this product when it was first released is tons of objectivists and subjectivists came together in agreement about how good this product was.
Now it's been a few years, a $100 price drop later, and the market is filled with so many more amps using the THX AAA technology. So does the THX 789 still hold up in the market at its current price? Is it still the sub $500 balanced king?
Specs:
General
- All parameters measured at 0 dB gain, 1 kHz, with balanced inputs and 300-ohm load unless otherwise noted
- Inputs: Stereo XLR-3 gold-plated Neutrik; Stereo RCA gold-plated
- Outputs: 1/4 in (6.35 mm) TRS gold-plated Neutrik; 3.5 mm TRS gold-plated; XLR-4 balanced gold-plated
- Frequency response: + 0.01 dB / - 0.03 dB 20 Hz–20 kHz; + 0.05 dB / - 0.15 dB 10 Hz–50 kHz
- Input impedance: 50 kOhms balanced or unbalanced
- Chassis: High-grade CNC-milled aluminum with bead-blasted finish
- Power supply: 24 VDC inline brick, universal input 100–240 VAC
- Dimensions: 8.3 x 9.1 x 2.2 in (210 x 230 x 57 mm)
- Weight: 3.4 lbs (1,520 g)
- Output power: 6000 mW, 16 ohms, <1% THD (watts per channel)
- Output power: 6000 mW, 32 ohms, <1% THD (watts per channel)
- Output power: 800 mW, 300 ohms, <1% THD (watts per channel)
- Output power: 400 mW, 600 ohms, <1% THD (watts per channel)
- THD: -143 dB, 300 ohms, 1 mW: 0.000007%
- THD: -140 dB, 300 ohms, 100 mW: 0.000010%
- THD: -130 dB, 32 ohms, 1 mW: 0.000032%
- THD: -130 dB, 32 ohms, 100 mW: 0.000032%
- THD: -122 dB, 16 ohms, 1 mW: 0.000080%
- THD: -122 dB, 16 ohms, 100 mW: 0.000080%
- IMD: -123 dB, SMPTE 70 Hz + 70 kHz, 300 ohms: 0.000071%
- IMD: -124 dB, DFD 18 kHz + 19 kHz, 300 ohms: 0.000063%
- Crosstalk: -127 dB, 300 ohms: 0.000045%
- Noise (A-wt): 2.4 uV, potentiometer at nil
- SNR: 136 dB, 300 ohms, <1% THD
- Gain: 0.66x , 2.0x, 6.6x (-4, +6, +16 dB), selectable via front switch
- Output impedance: < 0.1 ohms
- Output power: 3000 mW, 16 ohms, <1% THD (watts per channel)
- Output power: 1800 mW, 32 ohms, <1% THD (watts per channel)
- Output power: 200 mW, 300 ohms, <1% THD (watts per channel)
- Output power: 100 mW, 600 ohms, <1% THD (watts per channel)
- THD: -143 dB, 300 ohms, 1 mW: 0.000007%
- THD: -135 dB, 300 ohms, 100 mW: 0.000018%
- THD: -135 dB, 32 ohms, 1 mW: 0.000018%
- THD: -133 dB, 32 ohms, 100 mW: 0.000022%
- THD: -130 dB, 16 ohms, 1 mW: 0.000032%
- THD: -125 dB, 16 ohms, 100 mW: 0.000056%
- IMD: -117 dB, SMPTE 70 Hz + 70 kHz, 300 ohms: 0.000141%
- IMD: -125 dB, DFD 18 kHz + 19 kHz, 300 ohms: 0.000056%
- Crosstalk: -90 dB, 300 ohms: 0.003162%
- Noise (A-wt): 1.2 uV, potentiometer at nil
- SNR: 136 dB, 300 ohms, <1% THD
- Gain: 0.33x , 1.0x, 3.3x (-10, 0, +10 dB), selectable via front switch
- Output impedance: < 0.05 ohms
- Cloth Bag for the Drop + THX AAA™ 789
- Switching power supply that handles 100–240 VAC (US plug; adapter needed for global use)
- Manufacturer’s 1-year warranty
Another thing I want to mention and you may see it in some of the photos I post, but my AAA 789 had some weirdness in the metal housing where you could see lighter coloured swirls. It doesn't bother me but if you got a unit like this Drop would replace it for one without this issue. At least this QC issue doesn't affect performance.
There have also been some changes since the original batches.
- New volume knob that is easier to read.
- New logo
- New font
- New Finish on the housing
That's all the changes I was able to notice from memory.
The AAA 789 Came is a surprisingly large box that was extremely well padded. The Amp itself also came in a nice cloth bag. Not sure when you will use the cloth bag unless you plan to store the amp for longer periods of time.
The AAA 789 uses a completely metal build. With no round edged except on the front sides it's a very sharp square design, which gives it a very striking look. It's one of the most solid feeling amps I have used under $500. It's a 3 piece design, the front and back plates are separate, but the sides, top and bottom are all one solid block of metal.
It's fairly heavy so no need to worry about it moving on your desk during use. Big rubber feet which I love, so many companies put very small feet on their stuff. These feet also didn't mark up my white desk.
The only complaints I have would be the back corners are a little sharp and because of how the front 2 buttons are designed they are pretty scratchy when you push them in which hurts the very premium overall feel of using the amp.
Overall it has a nice heft to it and feels like a very well built product. While it may not have a big "Luxury' feel, it really doesn't need to.
I/O:
Front:
- Power Button: For turning on/off
- Balanced XLR Output: For connecting to your balanced headphones
- 6.3mm SE Output: For your Single ended headphones
- 3.5mm SE Output: For your Single ended headphones
- Power LED: White when on, red when protection circuit activates
- Gain Switch (-10, 0, +10 dB for SE / -4, +6, +16 dB for BAL): For switching Gain.
- Volume Wheel: Volume control
- Input Switch: Changing between headphone audio and the pass through.
Rear:
- RCA SE Input: For connecting to a SE DAC.
- RCA SE Pass-through: A SE Pass-through that works even with the AMP off.
- XLR Balanced Input: For connecting to a BAL DAC.
- DC 24/1.8A: The power input.
- Auto Off/Bypass Switch: Set the switch to Auto Off to have the AMP shut off after 2 hours of no audio.
- The Power Button has no tactile feel, but the amp does make a click sound inside the amp when turned on and off.
- The 3.5mm SE output is slightly recessed meaning some 3.5mm jacks may have issues.
- The power and input button are scratchy
- The addition of both a 6.3mm jack and 3.5mm jack I do really like, though I do find most people have at least one adapter laying around (many like myself have dozens). Either way I like seeing both. Though not completely necessary.
Sound
Jumping right into it, I am still happy to say that the AAA 789 still sounds great. But it's not for everyone. It still is a very Analytical/Sterile sounding AMP. The Bass is fairly dry, but overall it has fairly natural sounding treble for an analytical style amp that never really gets bright. The staging is also very nice, when this came out I would see a lot of people having issues with many amps having a very forward projecting stage and the depth all around stage that this had was very nice and still is.
The AAA 789 has a few big strengths sound wise, the first most people will notice is the very clean sound. The natural top end, and good staging next. But for me what impressed me most was it maybe has some of the best speed out of any analytical amp under $500. For me this is what really sets it apart from other options.
It's weaknesses are not so bad, there is really only one issue IMO. It does lack slam, that low end impact feels a little limp at times. I do find the quick attack does help somewhat make up for it but it still does sound a bit limp. Aside from that, the mid range I guess i'd say is a bit hazy, and the normal solid state micro-dynamic issue is present. Which by that I mean often they lack micro-dynamics, some will precise this as sounding almost slightly compressed, others they will just say it sounds boring or dull. But others will find this to mean it sounds more transparent and neutral. I'm in the former. Because of the lack of dynamics I wouldn't use it with headphones that are dynamically weak already.
Power: SE offers a respectable amount of power, it will be fine powering really anything but the crazy hard to drive stuff that I don't see many people using on this.
Balanced really offers as much power as anyone would ever need at over 3x the amount of the SE.
Sound Conclusion: Overall the THX 789 is still a fantastic take on that Objectivist Neutral sound. I call this type of amp analytical/sterile but in this case it doesn't have the normal analytical glare. So while this isn't exactly an AMP I would always use it still sounds fantastic for the price. If you're looking for something that will sound analytical/sterile and want very good speed, and overall great resolution and are ok with the slight lack of slam and micro-dynamics. Then sound wise this is a great option.
Conclusion
Overall while the AAA 789 isn't the be all and end all of amps that many people called it at launch it is still a fantastic balanced amp at $300 and still one of the better THX amps.
If the type of sound is something you're after and you're looking at a balanced amp under $400 I can highly recommend it. Overall I have no major complaints.
Pros:
- Great sound
- a decent amount of SE power
- Lots of Balanced power
- Solid metal design
- Smooth Vol Pot
- Protection circuit
- 3.5mm and 6.3mm SE jacks
- SE Pass through
- Big rubber feet
Cons:
- Slightly large
- Analytical sound isn't for everyone
- Limited availability
- No fully matching DAC
- Scratchy buttons
- No Pre-Amp
- Mine had cosmetic issues
Discussion Threads: