Sandisk Extreme Pro 400GB showed up in the HK Computer Mall stores (Shum Shui Po, -Golden Computer City) for a very reasonable price, HKD600 (USD75), so I picked one up to try. I hesitated, as I wanted a bigger card, and had no experience/conviction about whether it was worth getting, even though there are quite a few write ups about how the flash memory card can affect the audio playback sound, it somehow still did not feel real to me, so I flip flopped about getting it or not. Finally decided to try one, as I could always use a 400GB card in one of my other DAPs. (ZX300, ZX507)
So I formatted it in the WM1Z, and copied the 350GB of music from the old card onto it, and gave it a listen to see if I could sense any difference. I'll admit I did not expect much, other than the suspicion that that there might be a slight difference which would be hard to quantify.
Well, I am in shock.
The first think noticed was that bass was more solid and deeper. Continuing on, vocals had more micro detail, and voices had a clarity and purity in low level detail that was not present before. Sound was more immersive and emotive. PRAT/rythms better. The sound felt "live", compared to with the old MicroSD cards (Sandisk and Transend regular Class 10 cards). It is a significant upgrade to the sound, of a magnitude equivalent to a mod.
Let me quantify, though, that the differences may be considered small, but to me, are ultra important, as this is the area that I am interested in, and my system is aimed at, so to me, it is very significant, as it moves the music to be more involving, toe-tapping, musical. The differences I observe are felt, rather than measured. My gauge is whether it can pull me in, and I enjoy the music, and keep listening, without being bored, or losing attention. And I start to notice details in vocals, and a clarity, that I had not heard before. And I think I am hearing better Micro Dynamics (an Aminus term). And God forbid, that it does not put me to sleep, or leave me bored and not paying attention to the music, as has happened on some systems/music.
My theorizing about what is happening is that it has reduced the noise in the system, and as this is in the guts of the system, a reduction of noise has a major effect, to reduce the noise floor, and free up the processor, amps from the extra work of handling the noise, which the extra bass is a symptom of. And allows more micro details to be present, as it is not being masked. The effect is a more transparent and open sound, like a layer of graininess has been removed.
The equivalent that I can think of is when reducing the noise on the AC power in a home audio system. And then wondering how a change on the AC power resulted in stronger bass, better voice details, etc.....
After also trying the Exteme Pro on the ZX507 for awhile, I went back and got another 400GB card. It was a no-brainer purchase that I had no trouble justifying, to equip both main DAPs with the Extreme Pro MicroSD card. It is a bonus that the card is reasonably priced, and I would probably get it even if it cost more, after trying it out.
Highly recommended.