Review and Measurements of Massdrop THX AAA 789 Amp

[Jimster480]

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

No its just for connecting another amp to this amp.

 

[gvl]

No its just for connecting another amp to this amp.

Sigh. I've just stumbled on Monolith by Monoprice, dual AKM 4493s THX AAA headphone section, variable output or so it seems, analog input but SE only, all for $480. Intriguing.

 

[Jimster480]

Sigh. I've just stumbled on Monolith by Monoprice, dual AKM 4493s THX AAA headphone section, variable output or so it seems, analog input but SE only, all for $480. Intriguing.

Unknown DAC performance and the whole unit isn't yet measured.
So... if you want to buy it and send it to amir for the rest of us.... feel free

I did buy the THX 789 here without seeing any performance numbers, I was intrigued by the design and power output.
I basically replaced now both my O2 and A30 with this amp.

 

[gvl]

Unknown DAC performance and the whole unit isn't yet measured.
So... if you want to buy it and send it to amir for the rest of us.... feel free

I did buy the THX 789 here without seeing any performance numbers, I was intrigued by the design and power output.
I basically replaced now both my O2 and A30 with this amp.

There are some AP plots available for download on the product page for what they are worth. Too bad the MD unit has no variable outputs, as it would be exactly what I need to retire my O2/Schiit SYS stack

 

[Jimmy]

From what I understand the monoprice converts the analog input signal to digital for processing, the manual explains how to configure the parametric eq, the problem that I see is that it seems to be quite difficult to set everything up using the display and the volume knob, if it could be controlled using the computer with some software it would be better.

What's most interesting about these two units is the THX innovation in amplification technology, that puts many more expensive designs to shame. If it popularizes and more manufacturers use it, this will be a win for everyone.

 

[Jimster480]

From what I understand the monoprice converts the analog input signal to digital for processing, the manual explains how to configure the parametric eq, the problem that I see is that it seems to be quite difficult to set everything up using the display and the volume knob, if it could be controlled using the computer with some software it would be better.

What's most interesting about these two units is the THX innovation in amplification technology, that puts many more expensive designs to shame. If it popularizes and more manufacturers use it, this will be a win for everyone.

Topping A70 w/ THX AAA? xD

 

[gvl]

From what I understand the monoprice converts the analog input signal to digital for processing...

Dang, oh well, kind of makes sense actually given the onboard DSP.

 

[james]

From what I understand the monoprice converts the analog input signal to digital for processing

That makes sense given how Andrew M. said on the Q&A page that the volume control is "fully digital via AK4493 DAC." It would be interesting to see--if it is doing ADC--how good that is, and how controlling the volume in the DAC affects dynamic range. Too many questions for me to go in on the Monoprice before others have a chance to review it, and I agree with you that the menu system looks complicated, even to do something that should be easy like switching between the headphone and RCA outputs.

 

[maxxevv]

Unknown DAC performance and the whole unit isn't yet measured.
So... if you want to buy it and send it to amir for the rest of us.... feel free

I did buy the THX 789 here without seeing any performance numbers, I was intrigued by the design and power output.
I basically replaced now both my O2 and A30 with this amp.

You forgot about the DAC chip in this one ....

https://www.audiosciencereview.com/...of-topping-dx3pro-dac-and-headphone-amp.4967/

 

[Merkurio]

@amirm Could you measure the output impedance of the 3.5 SE output too?

Just for curiosity.

 

[amirm]

@amirm Could you measure the output impedance of the 3.5 SE output too?

I have. It is the same as 1/4 inch.

 

[Merkurio]

I have. It is the same as 1/4 inch.

I see, thanks.

 

[wadec22]

What is the current market price for these? Where are people doing the selling that has been mentioned?

 

[Jimster480]

You forgot about the DAC chip in this one ....

https://www.audiosciencereview.com/...of-topping-dx3pro-dac-and-headphone-amp.4967/

Yes but having the same chip doesn't mean the performance will be the same as we have shown here on this forum.

What is the current market price for these? Where are people doing the selling that has been mentioned?

I have seen people selling them for $500. But there are none on ebay right now.

 

[Sythrix]

I have seen people selling them for $500. But there are none on ebay right now

$500? They're crazy. If I was going to resell (which I don't see any reason I would) it would be for a hell of a lot more than that.

Besides the value within the fact that we all had to wait half a year for it to even release, there's eBay and PayPal (EDIT: and shipping) fees that would take down profit even further.

It's all ridiculous anyways, they're most likely going to drop again soon.

 

[Jimster480]

$500? They're crazy. If I was going to resell (which I don't see any reason I would) it would be for a hell of a lot more than that.

Besides the value within the fact that we all had to wait half a year for it to even release, there's eBay and PayPal (EDIT: and shipping) fees that would take down profit even further.

It's all ridiculous anyways, they're most likely going to drop again soon.

I saw a couple people posting on Massdrop with that price.

 

[maxxevv]

Probably people who can't live without a "warm and fuzzy" sound signature.

 

[Kyle / MrHeeHo]

Oh, that actually existing similar Monoprice product would be interesting if it measured well.

Monoprice has posted some measurements in a ZIP file at the bottom of the product page if you're curious

 

[rajapruk]

If you will measure this device more for some reason, I would like to know how much power it can output without going into protection mode in 8, 12, and 16 ohm loads.
The manual states that it can do 8-12ohm with reduced power.

 

[xineis]

Monoprice has posted some measurements in a ZIP file at the bottom of the product page if you're curious

I'm no expert, but it looks reasonable at least, right?