The amazon listing and my website both link to clear install instructions as well as stating that the header and standoffs are not included.
The install instructions can be found here:
https://drive.google.com/file/d/1b6Y6fvdK50TgxC3CAdWk2_2lO_vVovy9/view
Can you please let me know what instrument you are using to perform the measurements? I have verified the 128dB of SNR (A-Weighted) with both an Audio Precision APx515 and ATS-2. Also the 128dB would be for the balanced output, the RCA output will be 125dB.
Here is 24-bit silince A-Weighted (Mini-XLR Ouput 5Vrms is 0dB):
View attachment 14970
Here is SNR A-Weighted
View attachment 14968
Hi
Amir uses an APx555, but you are not comparing the same measurements here.
FOR DIGITAL CONVERTER MEASUREMENTS…
We recommend using this AES17 dynamic range measurement. It is intended specifically for ADC (analog-to-digital converter) and DAC (digital-to-analog converter) dynamic range and “noise in the presence of signal” measurements, as described in Section 9.3 of AES17. A similar method is defined in IEC61606.
This method differs from standard signal-to-noise and dynamic range measurements in that it uses a –60 dBFS stimulus during the noise measurement. This method is used for two reasons:
· In both ADCs and DACs, “idle tones” can be produced within the converter in the absence of applied signal. In the method here, a low-level tone is applied to the converter to avoid production of idle channel noise. The low-level tone is removed by a notch filter before measurement.
· In some DACs, the output of the device is switched off when there is no signal, providing an unrealistically quiet measurement. The low-level tone (again, notched out before measurement) defeats this muting mechanism.
At –60 dBFS, the tone is so low that any distortion products created are below the noise floor.
The 1794 does indeed support zero mute, is it active in your implementation? If so your measurement indicates the noise floor of the analyser.
Zero Detect When the PCM1794 detects that the audio input data in the L-channel and the R-channel is continuously zero for 1024 LRCKs in the PCM mode or that the audio input data is continuously zero for 1024 WDCKs in the external filter mode, the PCM1794 sets ZERO (pin 13) to HIGH.
The data sheet does use the AES17 method and shows this plot
Its a 32k FFT so FFT process gain is about 42 dB if I have done the maths right (highly unlikely) . So that would make Amirs numbers about right.
FFT gain = 10*log(M/2) where M= number of FFT points.
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