Just to add my experience in this area, and another option for MicroSD cards.
WARNING: People who do not believe SD memory can make a difference to sound should not read any further, as this article will raise your blood pressure with no benefit. Though thinking about this, the higher blood pressure to your ears may enhance the ability of the ear to translate sound waves to electrical impulses, and thus affect/improve what you hear.......
Others may find the discussion interesting....
- I had experienced what you describe when I first tried the Sandisk Extreme Pro, back in late 2020, and was quite surprised at the difference/improvement. I switched to the Extreme Pro for any further SD card purchase. (Also, it was affordable, so no big deal)
- Earlier this year (April), I got a Micron 256GB MTSD256AKC7MS-1WT 3.3V 256GB Micro SD. It was expensive, and only available from Mouser, but decided to splurge, as a distraction from Covid.
- First impression was not favorable, and using it for awhile(weeks), I was ready to give up on it, as the sound was noticeably worse than the Sandisk Extreme Pro. A bummer, as it cost USD125. Then remembered that previous discussions on this topic had recommended to use the SDFormatter (from the SD Industry) to do an overwrite (long) format using a PC, and then format on the Sony WM1Z which I was using, and then copy music onto it. This, and some burn-in, got it to sound like what other users had written about. At this point, I rated the Micron as the superior sounding card over the Sandisk Extreme Pro. But the problem was that it was so expensive....
- In mid Aug, I was at the Computer show, and saw a card that had been written about, but that I had not seen at the stores. This was a Kioxia Exceria High Endurance MicroSDXC 256GB card. (Kioxia is the rebranded name for Toshiba memory products.) Bought one for HKD390 (usd50) which was a more affordable price.
Took it home and tried it. used the SDFormatter overwrite format first, then format in the RS6. Really hoping that it would be decent sounding.
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And it sounds very good, on first use, and got better. Subjective opinion, this is now my preferred MicroSD card. And it is affordable, and available from local stores, or Amazon.
https://www.amazon.com/Kioxia-microSD-Exceria-Endurance-LMHE1G256GG2/dp/B089VTMJ33
- Did some research to see what it's specs are/why it is different. It's 3D NAND (94 layer?) I could not find whether it was MLC or TLC, but it is for sure a multi bit per cell, using 3D NAND technology, which stacks memory cells vertically. Think the 256GB is 94 layers. This structure is more complex, but uses less power, shorter access lines, lower latency. The complex and dense structure means that a lot of work has been done during development, to optimize power and noise, as the memory cell structure is so dense.
Edit: Exceria uses BiCS 3D Flash memory, which uses a different structure to create the 3D structure of the memory cells.
Another MicroSD available is from Transcend, which uses 3D NAND structure for their High Endurance MicroSD, similar to Micron
And it is the improvements in lower power and noise that I think are beneficial for Audio.
And the people who say bits are bits are correct. Bits are bits, even with cheap cards, but lower power and better noise performance comes with the more expensive industrial cards. And lower noise, from any part of a system, results in an improvement in any system. And noise does affect sound.
And once you start looking into it, SD memory is amazingly complex, with continuous work by the industry to increase memory cell density, and more efficient memory cell structures, and cell access methods.
Here is an article about current TLC 3D NAND technology using 232 layers, for Micron and SK Hynix 1TB chips. It's hard to imagine the complexity of a small MicroSD card....
https://www.electronicdesign.com/te...gn-memory-chip-makers-take-3d-nand-up-a-level
Some Youtube videos on 3D Nand:
