Here are some measurements of the audio outputs from a motherboard I just bought for my main workstation.
Equipment under test (EUT): MSI MPG Z390 GAMING PRO CARBON motherboard; front panel wired through a Fractal Design Define XL R2 computer case; standard HD Audio Microsoft driver (10.0.17763.1); Windows 10 build 17763; test signals played using FlexASIOTest 1.4 in WASAPI Exclusive Mode for bit-perfectness. EUT is running at 24-bit, 48 kHz, maximum gain unless otherwise noted.
Test equipment: QuantAsylum QA401 Audio Analyzer (using L-/R- inputs; L+/R+ properly terminated; attenuator disabled; baseline results); ASIO401 1.1; REW V5.20 Beta 6 and custom analysis scripts
All the raw data and measurements, including a few more not detailed in this post, can be downloaded here.
Before we begin, a few interesting things I noticed:
UNLOADED MAXIMUM OUTPUT VOLTAGE
Rear panel LR output: 7.1 dBV (2.3 Vrms)
Front panel output: 5.4 dBV (1.9 Vrms)
Nice to see around 2 Vrms output. This should be good enough for most use cases.
UNLOADED 997 Hz -1 dBFS SPECTRUM
Rear panel LR output:
THD: -84.9 dB THD+N: -83.1 dB
Front panel output:
THD: -88.0 dB THD+N: -84.1 dB
A result that won't make anyone jump up and down, but is in line with expectations for that kind of product.
DYNAMIC RANGE
Measured in accordance with AES17-2015 6.4.1 and IEC 61606-3:2008 6.2.3.3, unloaded:
Rear panel LR output: 102 dB CCIR-RMS (17 bits)
Front panel output: 103 dB CCIR-RMS (17 bits)
Not too bad considering the kind of product we're dealing with. The ads from the manufacturer claim 120 dB, which, unsurprisingly, is very far from reality (it looks like the manufacturer merely copy-pasted the figure from the Realtek ALC1120 datasheet).
UNLOADED THD+N VS. OUTPUT LEVEL
Measured in accordance with AES17-2015 6.3.4 and IEC 61606-3:2008 6.2.2.3.
Rear panel LR output:
Front panel output:
I'm not sure why there is so much variance in the rear panel measurement. I suspect it might have to do with poor noise isolation from computer activity, making the noise floor randomly jumping up and down. This would be consistent with the fact that the variance is reduced when a load is applied.
LINEARITY
Rear panel LR output (unloaded):
Front panel output (unloaded):
The step on the rear panel is quite weird. It's still there even after re-doing the measurement. The rear panel output also trends downwards at the lowest levels which is usually a bad sign as it suggests dithering issues. The front panel output is better behaved. On the other hand, the rear output still keeps within 0.5 dB down to around -110 dBFS (18 bits) which is pretty good, while the front panel output loses linearity at only -100 dBFS (17 bits). Still doesn't look particularly bad for this kind of product.
UNLOADED FREQUENCY RESPONSE
Rear panel LR output:
No objections here.
Spectrograms reveal a sharp reconstruction filter that compromises on imaging artefacts at the top end of the spectrum, which is pretty common. There are no artefacts to be found within the audible range, which is nice.
(spectrogram parameters: 20 dB gain, 100 dB range)
OUTPUT IMPEDANCE
Measured using a 15 Ω load and further confirmed using a 100 Ω load:
Rear panel LR output: 73 Ω (constant with frequency)
Front panel output: 101 Ω (constant with frequency)
Output impedance this high makes this product extremely unsuitable for driving most headphones. Manufacturer claims of a "dedicated headphone amplifier" are quite laughable in light of these results.
I did a few other measurements at 15 Ω and 100 Ω. Most of them didn't reveal anything particularly interesting, so I won't detail them here, especially considering the output impedance disqualifies this product for headphone use anyway. You can find them in the measurement package if you're interested. The only things worth noting is that I was unable to make the output clip into 100 Ω (1.16 Vrms max voltage, 13 mW max power), however, the rear panel output clips above -3 dBFS into 15 Ω, suggesting a current limit of around 18 mA.
CONCLUSION
As a basic DAC, performance of this product is average at best, but should be enough for most users. The comfortable output voltage (around 2 Vrms) is nice, and might interest users of high-impedance headphones. However, due to the extremely bad output impedance, this product is unsuitable for any kind of critical listening with most headphones; I would recommend treating these outputs purely as line-outs.
Equipment under test (EUT): MSI MPG Z390 GAMING PRO CARBON motherboard; front panel wired through a Fractal Design Define XL R2 computer case; standard HD Audio Microsoft driver (10.0.17763.1); Windows 10 build 17763; test signals played using FlexASIOTest 1.4 in WASAPI Exclusive Mode for bit-perfectness. EUT is running at 24-bit, 48 kHz, maximum gain unless otherwise noted.
Test equipment: QuantAsylum QA401 Audio Analyzer (using L-/R- inputs; L+/R+ properly terminated; attenuator disabled; baseline results); ASIO401 1.1; REW V5.20 Beta 6 and custom analysis scripts
All the raw data and measurements, including a few more not detailed in this post, can be downloaded here.
Before we begin, a few interesting things I noticed:
- According to the marketing material of the motherboard, it's supposed to have an headphone amplifier that "auto-detects impedance". I was unable to find any evidence of this; neither the front nor rear outputs seem to behave any differently with a 15 Ω load, 100 Ω load, or no load at all.
- The rear panel main stereo output is 6 dB louder (unloaded) than the other channels (surround, center, etc.). Be careful about level alignment when using more than 2 channels.
- I noticed this motherboard seems to be way more sensitive to ground loops on the audio outputs than my previous motherboard (a Gigabyte Z87X-UD3H). That said this is probably highly dependent on external factors, so YMMV.
- That's the first time I see a DAC that can be used in 32-bit in Windows. Which is of course pointless, but I found it amusing.
UNLOADED MAXIMUM OUTPUT VOLTAGE
Rear panel LR output: 7.1 dBV (2.3 Vrms)
Front panel output: 5.4 dBV (1.9 Vrms)
Nice to see around 2 Vrms output. This should be good enough for most use cases.
UNLOADED 997 Hz -1 dBFS SPECTRUM
Rear panel LR output:
THD: -84.9 dB THD+N: -83.1 dB
Front panel output:
THD: -88.0 dB THD+N: -84.1 dB
A result that won't make anyone jump up and down, but is in line with expectations for that kind of product.
DYNAMIC RANGE
Measured in accordance with AES17-2015 6.4.1 and IEC 61606-3:2008 6.2.3.3, unloaded:
Rear panel LR output: 102 dB CCIR-RMS (17 bits)
Front panel output: 103 dB CCIR-RMS (17 bits)
Not too bad considering the kind of product we're dealing with. The ads from the manufacturer claim 120 dB, which, unsurprisingly, is very far from reality (it looks like the manufacturer merely copy-pasted the figure from the Realtek ALC1120 datasheet).
UNLOADED THD+N VS. OUTPUT LEVEL
Measured in accordance with AES17-2015 6.3.4 and IEC 61606-3:2008 6.2.2.3.
Rear panel LR output:
Front panel output:
I'm not sure why there is so much variance in the rear panel measurement. I suspect it might have to do with poor noise isolation from computer activity, making the noise floor randomly jumping up and down. This would be consistent with the fact that the variance is reduced when a load is applied.
LINEARITY
Rear panel LR output (unloaded):
Front panel output (unloaded):
The step on the rear panel is quite weird. It's still there even after re-doing the measurement. The rear panel output also trends downwards at the lowest levels which is usually a bad sign as it suggests dithering issues. The front panel output is better behaved. On the other hand, the rear output still keeps within 0.5 dB down to around -110 dBFS (18 bits) which is pretty good, while the front panel output loses linearity at only -100 dBFS (17 bits). Still doesn't look particularly bad for this kind of product.
UNLOADED FREQUENCY RESPONSE
Rear panel LR output:
No objections here.
Spectrograms reveal a sharp reconstruction filter that compromises on imaging artefacts at the top end of the spectrum, which is pretty common. There are no artefacts to be found within the audible range, which is nice.
(spectrogram parameters: 20 dB gain, 100 dB range)
OUTPUT IMPEDANCE
Measured using a 15 Ω load and further confirmed using a 100 Ω load:
Rear panel LR output: 73 Ω (constant with frequency)
Front panel output: 101 Ω (constant with frequency)
Output impedance this high makes this product extremely unsuitable for driving most headphones. Manufacturer claims of a "dedicated headphone amplifier" are quite laughable in light of these results.
I did a few other measurements at 15 Ω and 100 Ω. Most of them didn't reveal anything particularly interesting, so I won't detail them here, especially considering the output impedance disqualifies this product for headphone use anyway. You can find them in the measurement package if you're interested. The only things worth noting is that I was unable to make the output clip into 100 Ω (1.16 Vrms max voltage, 13 mW max power), however, the rear panel output clips above -3 dBFS into 15 Ω, suggesting a current limit of around 18 mA.
CONCLUSION
As a basic DAC, performance of this product is average at best, but should be enough for most users. The comfortable output voltage (around 2 Vrms) is nice, and might interest users of high-impedance headphones. However, due to the extremely bad output impedance, this product is unsuitable for any kind of critical listening with most headphones; I would recommend treating these outputs purely as line-outs.
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