Review and Measurements of Massdrop THX AAA 789 Amp

[rajapruk]

it just doesn't feel right on moral level, man, how could they

I do not see any problem. If someone wants to buy for that price, why not.

And Amir's review is not anything new really, it is just a confirmation. The specs were out there from the beginning.

 

[Sythrix]

I do not see any problem. If someone wants to buy for that price, why not.

Just don't sell on ebay if you do. There's a 30 days return gurantee for buyers and if the drop goes live in that time, you're 100% getting a refund request; which will be granted by ebay, regardless of reason.

 

[rajapruk]

I am not selling mine. That was a joke.
Got them today!

 

[Grave]

I do not see any problem. If someone wants to buy for that price, why not.

And Amir's review is not anything new really, it is just a confirmation. The specs were out there from the beginning.

Specs are not good enough. THX's own measurements I would not trust. Jude at head-fi did some measurements, but I cannot think of anyone less trustworthy than him.

 

[March Audio]

This amplifier is. I have not measured any audio product with this low of distortion.

I will be measuring more high performance units but their cost will be multiples of this one so well above your budget.

What about this? Nearly here.

 

[Sythrix]

What about this? Nearly here.



View attachment 17095

Would have to remeasure at 5.7 volts for consistency, if possible, but very optimistic about that one as well. Looks like a great design.

 

[Grave]

What about this? Nearly here.

This is what?

 

[Headphonaholic]

This is what?

That would be the DAC amp he designed and will be releasing soon.

*Ooops! Said DAC but meant amp, got DACs on the mind

 

[March Audio]

That would be the DAC he designed and will be releasing soon.

Headphone amp not the dac

 

[March Audio]

Would have to remeasure at 5.7 volts for consistency, if possible, but very optimistic about that one as well. Looks like a great design.

It can't compete on power output, but I'm not really sure why anyone wants to put several watts into their headphones. However it can output 5 v rms which does account for most higher impedance cans.

 

[maverickronin]

It can't compete on power output, but I'm not really sure why anyone wants to put several watts into their headphones.

HE-5/6. Maybe a K1000 or two still hanging around.

Unlike speakers, headphones are easily shipped so people can go though buying and selling two dozen pair before they decide one or a few to keep. Having way more power than you need is more of an insurance policy than anything else.

 

[Sythrix]

It can't compete on power output, but I'm not really sure why anyone wants to put several watts into their headphones. However it can output 5 v rms which does account for most higher impedance cans.

Per Amir:

For consistency with my last couple of headphone amplifier reviews, I set the output at about 5.7 volts:

Most people probably wouldn't need that much, but this is where he's measured this amp and the previous standalone amps.

So for consistency's sake, they're not directly comparable for the time being.

EDIT: Maybe Amir would remeasure the THX 789 at whatever voltage he plans to use for your review, so a comparison could be made during?

 

[Sythrix]

HE-5/6. Maybe a K1000 or two still hanging around.

I always wanted to listen to monsters like these, just to see if the inefficiency translated to quality sound with ample power... or if they were just poorly engineered. Never even though about it at RMAF. Missed my chance, since the HE-6 re-release was probably there.

 

[maverickronin]

I always wanted to listen to monsters like these, just to see if the inefficiency translated to quality sound with ample power... or if they were just poorly engineered. Never even though about it at RMAF. Missed my chance, since the HE-6 re-release was probably there.

It's more about what kind of sound they were going for and low efficiency was the price to pay. Most of their target audience already had OTT headamps so from their perspective, why not?

The HE-6 actually have a pretty heavy diaphragm since the traces aren't aluminum or copper, but gold. Because of the greater weight it takes more power to move but you also get more vibration coupled to your skull and it gives excellent bass impact for a headphone.

A lot of their newer ones are more efficient than the HE-6 since they have thinner diaphragms with lighter traces from more conventional materials. They're still not as efficient as some other planars because lately (IIRC...) they been doing things with one-sided arrays of large magnets or double sided arrays of small magnets in order to minimize diffraction/reflection/acoustic impedance issues.

I like the 5 and 6 better than the newer HiFiMans I've heard (HEK, Edition X, Susvara). The thinner diaphragms they keep using kill the bass impact but still aren't as airy and clean as electrostats they're chasing. The 560 is still in production and supposed to have a fuller sound, but I haven't heard that one.

 

[Rod]

I always wanted to listen to monsters like these, just to see if the inefficiency translated to quality sound with ample power... or if they were just poorly engineered. Never even though about it at RMAF. Missed my chance, since the HE-6 re-release was probably there.

Well I put balanced cables on a 6xx and am happy about the extra power even with the 6xx's. According to the specs at 300 ohm it can put out 800 mW. I can turn it up as loud as I want and it stays clear with plenty of oomph.

 

[Sythrix]

Because of the greater weight it takes more power to move but you also get more vibration coupled to your skull and it gives excellent bass impact for a headphone.

The thinner diaphragms they keep using kill the bass impact but still aren't as airy and clean as electrostats they're chasing.

This would explain a lot. Has anyone experimented with using both a thick and thin diaphragm? Maybe in a multi-driver arrangement?

Now I want to try a pair of HE-6s even more.

 

[Jimster480]

I do not see any problem. If someone wants to buy for that price, why not.

And Amir's review is not anything new really, it is just a confirmation. The specs were out there from the beginning.

I'm actually totally fine with this concept.
If an amp's prices rises due to supply and demand because they made a product with impressive specs and then they delivered on these specs....
This is how the Audiophile market SHOULD work.
If you are paying, you should be paying for quality.
When products deliver said objective qualities and others notice and accept these qualities.... then that means people are paying attention here and that the audiophile market is being cleaned up.
It sure as hell beats spending $1200 on a device that gets beat by $100 devices, or $2400 on devices that are beaten by $79 devices (both have happened as shown on this forum).
Because this Amp has received great reviews (and there is alot of hype circling it due to their insane specs) now more and more people are interested in it.
Its literally how technology SHOULD work.
If only we had more Amir's for each tech subdivision

 

[maverickronin]

This would explain a lot. Has anyone experimented with using both a thick and thin diaphragm? Maybe in a multi-driver arrangement?

I don't know of any multi driver planars. It would probably work well if one made a coaxial. An HD800-like donut-ring planar diaphragm for the bass with something smaller in the middle from mids and treble.

OTOH, for some reason full size multiways (as opposed to IEMs) rarely seem to turn out well. They almost never sound properly integrated. THe best one I've ever heard was actually one of Final Audio's oddball dynamic balanced armature hybrids. It makes no sense, but I was stunned at how coherent it sounded.

 

[badboygolf16v]

Received mine yesterday and listened to it with a Khadas Tone Board, through AKG K181, HE-560 and ER4SR.

Sounds good, with very well controlled, powerful and clean bass being initially the most noticeable feature for me. Will be interesting to try my other phones, HD650 and K712 in particular.

Replaced a Benchmark DAC1 USB, and very happy with it.

 

[gvl]

Can it work as a pre-amp too? What the "RCA Pass" connectors on the back are for?