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Review and Measurements of Massdrop THX AAA 789 Amp

wadec22

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Must be a trend. My Monoprice Monolith shipped yesterday but has an expected delivery date of 11.29. I did their standard shipping of $10 for 3 to 6 business days. Guess it's going to take 8 business days not counting the holiday.
 

Headphonaholic

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My massdrop thx amp has yet to arrive even though I ordered it the second I received notification it was available. I haven't checked the tracking but last I knew I would be getting it Friday of this week... I could drive to their warehouse in less than 12 hours lol
 

Sylafari

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Got my Massdrop THX Amp in today. Sold the Questyle I had a while ago. Sounds transparent. Feels like an end game solid state amplifier for me. :cool:
 

pkane

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My new favorite. Received it from Massdrop two days after ordering. Works very well with HE560s, balanced in and out, 6m cable. Sounds detailed and transparent, excellent bass control, no hum or background noises. I'll try it with HD650s next.

Tested THX AAA 789 (needs a shorter name) with HD650s. Better, more natural sounding than HE560s that already sounded excellent. Both were DSPed to a similar, 5dB inclined linear frequency response over 20-20KHz using in-ear microphones and level matched for comparison.
 

TheBatman_Yo

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Got my Massdrop THX Amp in today. Sold the Questyle I had a while ago. Sounds transparent. Feels like an end game solid state amplifier for me. :cool:

I'm curious, does anyone have measurements of Questyle's DAC/amp combos? I'd like to know how well the CMA400i performs simply because I was considering purchasing it before I learned about the THX 789.
 
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amirm

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I'm curious, does anyone have measurements of Questyle's DAC/amp combos? I'd like to know how well the CMA400i performs simply because I was considering purchasing it before I learned about the THX 789.
I have never had one for review so no measurements here. Distortion specs they have for the headphone output at 300 ohm is 6X worse than THX 789. The 789 also has 150 milliwatts of output versus 100 for CMA400i.
 

Sylafari

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I'm curious, does anyone have measurements of Questyle's DAC/amp combos? I'd like to know how well the CMA400i performs simply because I was considering purchasing it before I learned about the THX 789.

I owned a Questyle CMA 800R, it was just a headphone amplifier. It came with a piece of paper of its measurements, I believe I have a photo of said measurements and the interior of the amplifier somewhere on the forum still.
 

Roen

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Can Single Ended Source feed Balanced output and vice versa?
 

Roen

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Any headphones out there that don't get loud enough with a 2.1Vrms DAC on highest gain on SE output? Forcing you to use balanced output on medium gain?
 

derp1n

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What is the implication of this statement? ELI5 please?
It's the usual audiophool rubbish, I wouldn't worry about it at all.
 

Roen

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It's the usual audiophool rubbish, I wouldn't worry about it at all.
But what does it mean? No offense, and I appreciate the sentiment, but I'd personally like to be the judge of whether something worries me or not.
 

Veri

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But what does it mean? No offense, and I appreciate the sentiment, but I'd personally like to be the judge of whether something worries me or not.

I believe balanced inputs get converted to single-ended and then goes back to balanced for output, hence the "opamps in the balanced output path". The alternative would be symmetrical independent circuitry and is therefore much more costly. As you can see in the measurements though, there's no real apparent downside to this cheaper approach. But audiophile's don't like it so I guess it must sound bad :D.. I think it stems from a dislike to opamps, but as we can see here the THX engineers know what they're doing.
 

Roen

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Ok, i had guessed that's what it meant, that the amp wasn't fully differential balanced.

Can't really say there's any objective tests out there that one can tell the difference between volume matched differential balanced vs op amp balanced, let alone balanced vs. SE, as long as power isn't an issue.
 

Veri

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Can't really say there's any objective tests out there that one can tell the difference between volume matched differential balanced vs op amp balanced, let alone balanced vs. SE, as long as power isn't an issue.

I would be inclined to agree with that, yes :)
 

VonGoethe

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Hi,
will the Massdrop THX AAA 789 combined with the RME ADI 2 DAC an upgrade over the amp of the ADI 2 DAC?
 

westyjeff

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The headphone amp in the ADI 2 is very good, and I mean really good but the THX 789 gives you more headroom for inefficient headphones and has the clarity to amplify the ADI 2 beyond what you will ever need.. This is what I use a I like them both very much!
 

VonGoethe

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The headphone amp in the ADI 2 is very good, and I mean really good but the THX 789 gives you more headroom for inefficient headphones and has the clarity to amplify the ADI 2 beyond what you will ever need.. This is what I use a I like them both very much!
I drive a Denon D7200 (25 ohms) with the ADI 2 DAC, which is very modest.
Maybe I can save me the money for an extra amplifier.
 

Roen

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Anyone know of any 1.05Vrms SE / 2.1Vrms BAL DACs out there?
 
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