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Review and Measurements of Monoprice THX Desktop DAC & Amp

amirm

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#22
That would be just an amp correct? Can you recommend a DAC to go with it?
Yes (as is the massdrop THX). You can go with Topping D10, Schiit Modi 3, Topping D50 (matches its looks well), or SMSL SU-8.

If you want an integrated unit, the Topping DX3 Pro continues to be my choice even though some people have had reliability issues with it.
 

Tks

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#23
Yes (as is the massdrop THX). You can go with Topping D10, Schiit Modi 3, Topping D50 (matches its looks well), or SMSL SU-8.

If you want an integrated unit, the Topping DX3 Pro continues to be my choice even though some people have had reliability issues with it.
My brother got the DX3 Pro today. The functions caught me off gaurd, and the remote is lovely (I got an Nvidia Shield with an absolutely idiotic version of what this remote is).

Even tested the Bluetooth on iOS for a few minutes. Easy quick pair-up, and was playing music from laying down in bed :)

This thing is amazing and feels even better than it look if you ask me personally, pretty much jealous right now. Oh and for others reading this, it came with the latest firmware. Also it was from Massdrop with an ETA ship-date that was May 13th if I recall from what my brother told me. Boy did they deliver.

For the price, this thing murders. Honestly... in general it's simply amazing.
 

amirm

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#24
For the price, this thing murders. Honestly... in general it's simply amazing.
Indeed. There is a reason I use it everyday myself. Puts a smile on my face every time I look at it.
 

Veri

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#25
Examining the nature of the noise and distortion relative to power showed something odd:

View attachment 25813

The rising distortion relative to noise is unfortunate but there is a sudden drop indicating that the frequency response is limited. I ran the test up to 40 kHz and got this:

View attachment 25814

So a roll off is occuring. Are the analog inputs digitized? They seem to be given the perfect channel balance relative to volume knob:
I believe what we're seeing here is the chain analog>digital with a digital filter, and then back from digital>analog with a select digital filter.
AKM 'Velvet Sound' in action :)
 

vkvedam

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#26
Thanks Amir, it was a good read.

Couldn't help but notice, you have a Stax SRM-007t underneath, planning to measure this :)
 

bunkbail

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#28
Thanks Amir, it was a good read.

Couldn't help but notice, you have a Stax SRM-007t underneath, planning to measure this :)
Maybe a dumb question, is it possible to measure an electrostat amp? I figure the voltage output would be very high for the AP analyzer to handle.
 
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#29
Yes (as is the massdrop THX). You can go with Topping D10, Schiit Modi 3, Topping D50 (matches its looks well), or SMSL SU-8.

If you want an integrated unit, the Topping DX3 Pro continues to be my choice even though some people have had reliability issues with it.
Got my hands on a JDS Labs Atom for a very good price so I am looking for a DAC to go with it from your list.

I can get hold of the Topping D10, Schiit Modi 3 or the Topping D50.

I am really torn between the three, any recommendation?
 

JohnYang1997

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#30
Same as I expected. They used ad8397 as their output ic. It has higher current output than most ics. But it is no where near the performance of thx 789. I don't want to call it thx technology which there is no sign for it to be an innovative technology. Just well engineered circuit using off the shelf parts.
As this one has even higher noise than dx3pro(which I have a little complaint about noise), it becomes less competent for me.
(They should have used tpa6120 in a composite amplifier configuration which is going to be even better than thx 789)

However, DIRAC is certainly interesting. Instead of pursuing perfect waveform reproduction, dirac will introduce a new experience. As the soundstage didn't really exist, the reproduction of soundstage of speakers is likely to be fun and meaningful.
 

amirm

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#32
so is the dashboard averaged? is that why the noise doesn't show up in the graph?
The FFT is. It is averaged 3 times with 32K points. It is the latter which reduces the apparent noise floor to be much lower than it really is. Ignoring the FFT window, the gain/reduction of noise floor in the FFT display is around 42 dB.
 

amirm

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#33

amirm

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#34
Got my hands on a JDS Labs Atom for a very good price so I am looking for a DAC to go with it from your list.

I can get hold of the Topping D10, Schiit Modi 3 or the Topping D50.

I am really torn between the three, any recommendation?
I have a rule in purchasing things in general: if you can't decide, buy the cheapest. :) That would be D10. It is so cheap that if you want to get something else in the future, it won't be a big deal. I love the display on it and it can act as USB to S/PDIF converter. Note however that its only input is USB though.
 

JohnYang1997

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#35
Since there isn't head tracking, it's possible to extract the impulse response of the dirac. Just excite impulse to left and right individually and collect both left and right channel each time. So there will be 4 impulse responses.
If one channel is intact, it's 100% malfunctioning. I would like to see what the new unit can do.
 

amirm

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#37
@amirm Just notice that you've got SINAD in here at approx 106.5 but on the chart, you've got it grouped/labelled in the 105s.
Yeh, I need to fix that. I confused myself with the portable THX unit as I went to enter it in the chart, thinking it was already there...
 
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#38
I played with Dirac in their portable product. It is not that effective and does odd things to one channel. See: https://www.audiosciencereview.com/...ice-portable-amp-and-dac-with-thx.5189/page-3
DIRAC on this unit makes a pretty noticeable difference. The latest firmware fixed an issue with it using analog RCA source input too. I noticed that DIRAC definitely makes a holographic soundstage to songs. Some songs sound really nice with it on (acoustic music for example) and some songs (heavier bass music, for example) sound pretty bad.
 

TonyNL

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#40
Is the noise at this level audible with a very detailed headphone? Like a planar or better asked what kind level of headphone do you need before you start to hear any difference?
 
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