Test Setup:
Audio Precision APx555 B-Series Analyzer with 200kOhm input impedance
Van Damme Star-Quad shielded SPC XLR cables with Amphenol Connectors
USB Source: AMD PC via ifi iGalvanic 3.0
Audioquest Carbon USB and SPDIF cables
All measurements shown in this post are taken with SPDIF input, 44.1khz sample rate and stock vivid filter unless otherwise noted [other input/filter measurements available in reports]
Full reports containing additional data and test configurations are attached
Exact analyzer/filter configurations for each measurement are detailed in the full reports
APx Project is included in the reports folder should anyone wish to repeat this set of measurements or use it for another DAC
ChitChat:
This DAC is an interesting one, its quite pricey at about $1500, and offers a few extra/unusual features. Its not quite the same insert ESS chip and Opamp here for 122dB SINAD design, with 10Mhz clock input support, a discrete Class A output stage [with analog LPF] , and a fair amount of extra DSP and clock related stuff.
As a result, this costs twice the price of something such as a D1SE. Whether that is worth it is another question. At $1500 its knocking on the door of a lot of very well regarded DACs like the Yggdrasil, Spring 3 etc.
If there are any other measurements youd like to see theyre most likely in the reports. But if not, let me know and Ill add them to my sequence for future tests.
Full Reports:
Reports available here:
Reports contain the following measurements:
1khz Sine View
15khz Sine View
-90.31dBfs Sine View
Phase Response
Filter Ultrasonic Attenuation
20hz-90khz RMS Noise Level
Device Output Level [Vrms]
20hz-20khz Noise RMS Level
Idle Noise FFT
1khz FFT [0dBfs and -3dBfs]
50hz FFT [0dBfs and -3dBfs]
Effective Number of Bits [0dBfs and -3dBfs]
THD+N [0dBfs and -3dBfs]
THD+N / Frequency
Dynamic Range [AES17]
SNR
IMD [SMPTE]
50hz/7khz IMD SMPTE FFT
IMD SMPTE vs Output Level
Linearity
Linearity [No Bandpass]
SINAD/Output Level
Crosstalk / Frequency
DC Offset when Active
DC Offset when Idle
44.1khz Jitter
48khz Jitter
90khz Bandwidth test
32 Tone FFT
1.2Mhz Bandwidth Noise FFT
1.2Mhz Bandwidth 1khz FFT [0dBfs and -3dBfs]
And more!
Measurements:
Dynamic Range [AES17]:125.4dB
SNR:127dB
Noise Level RMS [20-20khz]:2.264uVrms
Noise Level RMS [20-90khz]:4.405uVrms
DC Offset:567uV Active, 461uV idle
1khz 0dBFS:
Pretty crazy THD+N performance, BUT:
1khz -3dBFS:
Actual SINAD figure is still very good, but it is rather odd that once we stop playing a full scale signal the 3rd harmonic in particular is suddenly almost 15dB higher..
Not sure if this is an unintentional quirk or something done specifically to optimise for looking good in test conditions.
THD+N / Frequency:
Linearity:
SINAD/THD+N vs output level:
IMD [SMPTE] vs Output Level:
Crosstalk:
-90.31dBfs 1khz Sine [Recorded with 192khz ADC Sample Rate]:
Filter Ultrasonic Attenuation:
Gustard says this is a custom/proprietary filter, but it seems to be identical to ESS Fast Linear filter.
D1SE Fast Linear vs Gustard Vivid filter shown below, can you tell which is which?
Impulse Response:
Gustard also says it supports NOS. Which is confusing becausewell..you cant really run a delta sigma dac in NOS.
Looks like the NOS option is basically a VERY short minphase filter:
Was sort of expecting a Zero-Order-Hold filter on this one similar to RMEs NOS/Super-Slow filter on the ADI-2 which does actually produce a result similar to what youd expect from a NOS dac.
Idle Noise Spectrum upto 1.2Mhz:
Analog Low Pass FIlter:
Gustard mentioned the analog low-pass filter so I checked that, 192khz input:
44.1khz Jitter [USB]:
48khz Jitter [USB]:
Multitone:
No matter what I did, I struggled to get a result on this test where the