Massdrop x THX AAA™ 789 Linear Amplifier - Impressions Thread
Dec 3, 2018 at 11:25 PM Post #466 of 2,613
uhhh that I'm not sure, maybe someone can offer a scientific reasoning for that. All I know is these are not truly balanced amps, so they are all converting SE in to BAL out. I mean if you have 6xx its not that hard to get a balanced cable for that.

Yes I do plan on getting a balanced cable for my 6XX at some point. I thought the 789 was truly balanced as it has balanced inputs on the back? Also if I were to get a balanced DAC to pair with it what would be a good recommendation? I have not seen the Massdrop SDAC balanced get dropped for a long time.
 
Dec 3, 2018 at 11:27 PM Post #467 of 2,613
Yes I do plan on getting a balanced cable for my 6XX at some point. I thought the 789 was truly balanced as it has balanced inputs on the back? Also if I were to get a balanced DAC to pair with it what would be a good recommendation? I have not seen the Massdrop SDAC balanced get dropped for a long time.
See previous post I asked the same question(at page 29 or something). They say this is not truly balanced, so no point to get balanced dac(but you can anyway).
 
Dec 3, 2018 at 11:29 PM Post #468 of 2,613
See previous post I asked the same question(at page 29 or something). They say this is not truly balanced, so no point to get balanced dac(but you can anyway).

Hmm okay. Then what is the point of including balanced inputs?
 
Dec 4, 2018 at 12:50 AM Post #470 of 2,613
Supposedly the dual XLR-in to balanced-out pathway eliminates several potential extra paths that the RCA-in has to go through.

Hmm okay. Not really familiar with the technical stuff behind that so maybe it’s no big deal for me.
 
Dec 4, 2018 at 3:20 AM Post #471 of 2,613
Received mine. I don't have much impression other than it's a solid SS amp that seems way too good for its price. Compare to my SPL Phonitor, the only thing that I noticed it's FAST. It does imaging slightly differently. This little thing is easily matching my SPL in power and clarity.

Pros:
- drive THREE headphones at the same time as long as you are not exceeding the electrical capabilities of the amp. Do your own math before you plug in three ultra-low impedance headphones: 1/Rtotal = 1/R1 + 1/R2 + 1/R3
- Line pass-through without powering the amp on
- black background. should be fine for your IEMs

Cons:
- Volume pot does not go completely silent
- Super low volume has channel imbalance
- Gain1 position has a crosstalk issue. Probably not audible in most cases, but people have noticed it.

I dont get your issue with the volume being silent. When i turn the volume all the way down with source still playing its dead silent. I’ve not tried with the unit off since its on all the time. Everything with a pot will have low volume imbalance. only way around that is digital volume control to my knowledge.
What are the symptoms of the crosstalk issue? I’ve used mine in se before and heard no difference with any gain setting, and I’m using balanced out now with also no difference besides the gain as i switch. Is the issue on balanced and se in low gain or just one of them? Is this something audible or are they using an actual meter to measure crosstalk in the different gain settings?


I gotta edit my statement. I never noticed it before bc i was using low gain and the laptop next to me is kinda noisy with fan. i switched gain and listened and i do hear the music when the volume is turned down all the way.
 
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Dec 4, 2018 at 3:47 AM Post #472 of 2,613
What are the symptoms of the crosstalk issue? I’ve used mine in se before and heard no difference with any gain setting, and I’m using balanced out now with also no difference besides the gain as i switch. Is the issue on balanced and se in low gain or just one of them? Is this something audible or are they using an actual meter to measure crosstalk in the different gain settings?

I've seen a picture with measurements data on crosstalk issue here: https://www.audiosciencereview.com/...-of-massdrop-thx-aaa-789-amp.5001/post-117628
 
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Dec 4, 2018 at 8:26 AM Post #474 of 2,613
I dont get your issue with the volume being silent. When i turn the volume all the way down with source still playing its dead silent. I’ve not tried with the unit off since its on all the time. Everything with a pot will have low volume imbalance. only way around that is digital volume control to my knowledge.
What are the symptoms of the crosstalk issue? I’ve used mine in se before and heard no difference with any gain setting, and I’m using balanced out now with also no difference besides the gain as i switch. Is the issue on balanced and se in low gain or just one of them? Is this something audible or are they using an actual meter to measure crosstalk in the different gain settings?


I gotta edit my statement. I never noticed it before bc i was using low gain and the laptop next to me is kinda noisy with fan. i switched gain and listened and i do hear the music when the volume is turned down all the way.
crosstalk - I clarified that it shouldn't be audible in a later post

low level channel imbalance - yeah theoretically all analog pots will have it. But you can engineer it to not-audible levels. I certainly can't hear any imbalance with my SPL, but that was originally a $700+ amp
 
Dec 4, 2018 at 11:56 AM Post #475 of 2,613
Good question.....My home office has my desk, where one is located and gets the most use. The second one is about 10ft away and is for use when I'm on my exorcise bike, which I log time on daily. They both connect to my Yggy and are controlled by Roon.
I am curious if you connect one through XLR and the other through RCA or use some kind of XLR switch, or plug/unplug cables by hand when you move from one amp to the other? I figured balanced cables can be run long way without SQ degradation.
 
Dec 4, 2018 at 7:55 PM Post #476 of 2,613
Just got mine. Compared to my Magni 3, its no brainer. I have no more insight than anything out here. Just one question, is there any benefit to use the magni as a preamp? (something like Modi3->Magni3->THX AAA 789)

Also, through SE, with my HD6XX, I need to use gain III at 12 o'clock to get satisfying volume, so it seems that it is not that powerful through SE. But I already ordered a balanced cable so not too worry about it.
 
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Dec 4, 2018 at 8:13 PM Post #477 of 2,613
WeChat Image_20181204201245.jpg

Oh yeah another question, when I try to connect the power adapter to the power plug, it's pretty loose, and I can't force it to get any deeper. Take a look at the pic here
 
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Dec 4, 2018 at 8:38 PM Post #478 of 2,613
hey all.

I have an incoming unit.

Was wondering if i can use a 24V4A DC LPS to power the unit instead and if there will be any benefits?

Thanks!
 

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