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Review and Measurements of Monoprice THX Desktop DAC & Amp

Darvantus

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friend of mine wants to give me his pair for the cost of gas. Can't really repick a pair of $3 headphones.
 

odyo

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I get excited when i discovered this one. It's like poor man's RME ADI 2. Aesthetically even better but... didn't like the performance. When someone gonna do all in one dac/amp with the performance of top notch stacks and with some features like screen, eq and dirac also beautiful design like this ? Topping put your E30/L30 inside a DX7 pro case. Fiio actually doing it but i guess it will be a bit expensive.
 
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amirm

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A member sent another sample of this to me to measure the headphone amplifier alone. Here are those results.

First with 1/4 inch headphone jack:

Monolith by Monoprice Desktop Balanced Headphone Amplifier and DAC with THX AAA Audio Measurem...png


And with XLR "balanced" out:

Monolith by Monoprice Desktop Balanced Headphone Amplifier and DAC with THX AAA Balanced Audio...png


The latter is identical to what I measured with digital input in the review showing that the amplifier noise is the bottleneck.
 

Veri

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The latter is identical to what I measured with digital input in the review showing that the amplifier noise is the bottleneck.
Remember, the analog inputs on this device are digitised to allow the EQ/crossfeed functions. So makes sense it is close to digital input ;) in fact that means a good ADC is used.
 
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Tks

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Remember, the analog inputs on this device are digitised to allow the EQ/crossfeed functions. So makes sense it is close to digital input ;) in fact that means a good ADC is used.
Does that mean the RME does the same since you can also output DSP applied analogue out from the outputs?
 

Veri

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Does that mean the RME does the same since you can also output DSP applied analogue out from the outputs?
Umm if DSP features are available on the analog inputs, then yes they are for sure going through a digitisation process.
 

Tks

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Umm if DSP features are available on the analog inputs, then yes they are for sure going through a digitisation process.

O snap, you said analog inputs, I thought you mean't outputs, that's why it threw my off. Now I'm confused even more though. What are analogue inputs that are digitized as opposed to non-digitized? Non digitized would be what exactly, an analogue passthrough or simply an amping of the signal or something?
 

Veri

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O snap, you said analog inputs, I thought you mean't outputs, that's why it threw my off. Now I'm confused even more though. What are analogue inputs that are digitized as opposed to non-digitized? Non digitized would be what exactly, an analogue passthrough or simply an amping of the signal or something?
Well yeah no DSP would mean the inputs are processed by the amp (or even hardware crossfeed or EQ is possible but more rare) but digital processing absolutely requires a conversion to a digital format, to then process back to a DAC, to then finally be amplified which can take a hit on SNR, of course.
 

yakman

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Anyone tried powering this unit with a linear power supply (compared to its stock "phone charger")?
 

Veri

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Anyone tried powering this unit with a linear power supply (compared to its stock "phone charger")?
Phone charger? It's a 16.5V PSU, your phone will not take to that kinda voltage :p
 

yakman

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Phone charger? It's a 16.5V PSU, your phone will not take to that kinda voltage :p
well, many phones today, at least Android ones with fast charge, taking that voltage easily ; )
 
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Monstieur

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My unit seems to have an issue where the channel balance randomly swings left or right, and then recentres after a while. It's very evident on mono / centred content like YouTube videos. This happens on both XLR and USB inputs. I first thought it was from my Steinberg audio interface going into the XLR input, but it's definitely the Monolith because it happens on USB as well.
 

Darvantus

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My unit seems to have an issue where the channel balance randomly swings left or right, and then recentres after a while. It's very evident on mono / centred content like YouTube videos. This happens on both XLR and USB inputs. I first thought it was from my Steinberg audio interface going into the XLR input, but it's definitely the Monolith because it happens on USB as well.
Youtube is not a great basis, as often videos are recorded in mono or when uploaded are converted to mono. Do you experience that with movies or tv, not on youtube?
The reason i ask, is there are some videos in which i get no sound at all, not just on one amplifier (as i have multiple)
 

Monstieur

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Youtube is not a great basis, as often videos are recorded in mono or when uploaded are converted to mono. Do you experience that with movies or tv, not on youtube?
The reason i ask, is there are some videos in which i get no sound at all, not just on one amplifier (as i have multiple)
The point was the signal is identical on both channels, but the amplifier skews to one side. While content is playing, I can hear the audio panning and coming to rest on one side. This happens randomly and returns to normal after a few minutes. While the balance is skewed, playing a full scale test tone results in distortion in the louder channel. Reducing the volume on either the amp or in software avoids the distortion.
 
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Darvantus

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The point was the signal is identical on both channels, but the amplifier skews to one side. While content is playing, I can hear the audio panning and coming to rest on one side. This happens randomly and returns to normal after a few minutes. While the balance is skewed, playing a full scale test tone results in distortion in the louder channel. Reducing the volume on either the amp or in software avoids the distortion.
It actually was the point, have you noticed same issue with other sources, not youtube? Music? Movies? Tv?
 

Monstieur

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It actually was the point, have you noticed same issue with other sources, not youtube? Music? Movies? Tv?
Yes it happens with everything including test tones.
 

brachypelma44

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After researching for a couple of days, I pulled the trigger on this one. Monoprice has it on sale for $400 right now, and for my very simple needs (PS4 Pro -> optical -> Monolith --> headphones) it should be really good, bordering on overkill. I won't run into the analog input conversion issue since I'm using a digital source, and they already fixed the volume knob issue with a firmware update. Cannot wait for it to show up! :D
 
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silver2545

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After researching for a couple of days, I pulled the trigger on this one. Monoprice has it on sale for $400 right now, and for my very simple needs (PS4 Pro -> optical -> Monolith --> headphones) it should be really good, bordering on overkill. I won't run into the analog conversion issue since I'm using a digital source, and they already fixed the volume knob issue with a firmware update. Cannot wait for it to show up! :D
What's this firmware update you speak of? Mine us running v1.04 and the version I can see on the Monolith site is v1.03
 

brachypelma44

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What's this firmware update you speak of? Mine us running v1.04 and the version I can see on the Monolith site is v1.03

I have been to so many sites and watched so many videos in the last couple of days researching this unit that I don't remember where I heard about the volume knob issue being fixed in a firmware update. If this information is incorrect, I apologize.

I doubt the volume knob will be a major issue for me, as I do most of my music listening before bed, when my wife and dogs are already asleep. I don't have situations where I need to turn it down in a hurry at that time of night.
 
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