I watched carefully these two youtube videos ... As they are mostly concerned with sample rates issues, long distance inter systems transmissions and ADC/DAC conversions (with mainly jitter issues for D/A Conversion ), I am not sure, these videos are applicable to some WM1AM2 SD card types or internal memory, all through some pure Digital buffer readings before conversion.
I really doubt that in the Sony's WM1AM2, the internal components, cable length or solders are such low quality that some jitter could impact/create some audible distortion in the digital to analog conversion time.
And even if there are some really low quality components in the WM1A, it's still not clear how fewer readings errors could transform theoretically fewer scratches/cuts into "stage width/depth" or clarity in low or high frequencies.
Thanks for sharing your detailed thoughts on this.
Sorry but I have to go really technical on this to explain to you. Do note I do not have a degree in electrical engineering and all these information is gathered from my own interest in understanding how digital audio reproduction works at a deeper level.
Perfect Digital transmission without bit errors is not possible at the moment due to voltage skew errors that happens with electricity flow in the printed circuit board and the Data transmission receiver circuitry that determines if the voltage swing is a One or a Zero.
EMI noise is quite a pervasive issue that affects all digital devices. FCC do have EMI regulations that electronic devices must pass in order to be sold in the USA.
Certainly the Sony Walkman Engineers and also, A&K, Caylin, FiiO, Shanling and IBasso DAP engineers all do pay special attention to reducing the effects of jitter caused by electrical, radio, magnetic as well as physical vibrations at the printed circuit boards.
However there’s still a technical limit, physical size, design costing, manufacturing difficulty considerations to how much jitter/interferences that can be reduced. I think for these DAP designers, they have already done the best they can from the considerations to achieve what they consider as “good enough” low jitter for high quality sound reproduction. What is good enough? Well it depends on how golden your ears are.
You can say Sony is quite good at shielding their higher end Walkman from EMI/RFI noise, some other audio devices like chord mojo will likely buzz digital noise when there’s a mobile phone transmitting mobile data next to it which doesn’t happen to Sony Walkman (unless you happen to own a pair of ultra sensitive iems)
There’s still one area of EMI noise transmission that cannot be totally eliminated with use of extensive copper shielding and that is the microSD cards electrical and data pathways that leads to the Walkman battery and Its NXP CPU. I would think that is the likely method that an electrically noisy microSD can affect the Walkman highly precise crystal word clock timing output.
I would think It’s kinda of like a butterfly effect, as long as the crystal work clock timing is off by a few picoseconds, it will result in cumulative timing error issues(jitters) with the dac output. This errors don’t noticeably affect the frequency response of the Device but these errors may affect the phase timing which in turn affects the perceived sound-staging and sound localisation of the human ear. This errors might not be noticeable to untrained ears but to certain group audiophiles with trained/experienced ears, they can notice this errors.
Also there are error correcting systems like Phase Lock Loops which can sort of mitigate jitter problems but it has its own limits to how much can be done, if there’s too much data transmission issues, the PLL will unlock. Digital systems are pretty robust from an error correction point of view but in the case of high precision audio reproduction is concerned where by millions of bits are flowing through every second, these unpredictable undetermined transmission errors and picosecond timing errors will affect the final sound quality output to a certain extent.
It’s really a very complicated electrical design issue requiring deep understanding of science and how energy transmits. I guess I will end right here.