What's the BER of a $5 SDHC card? About 10^-15 perhaps (uncorrected).
What's the BER of this card? I'm guessing around 10^-15 or so (uncorrected).
So, bit error rate is essentially zero for most intents and purposes. Let's move on...
Someone mentioned that the emissions graph says that it is radiated. Ok, so if this is true then we've got some possible scenarios where the $$ card produces audio with a higher noise free dynamic range.
scenario #1 - the SDHC card is mounted direcly above the ADC section - don't laugh - if the product is tiny, there can be a lot of compromises in placement of parts, where marketing wants certain features, etc. - Maybe the ADC isn't above the SDHC card, or under it, but perhaps the emissions are enough to alter the ADC noise AND/OR produce mixing products. Maybe that 1,2,5 or so MHz emission is mixed down INSIDE the ADC and it is now planted in your band of interest and untouchable by your filtering. Maybe a remnant of the emissions remains on the supply rails where, if synchronous, can still take serious filtering to mostly remove.
scenario #2 - if the read clocking of the SDHC ever becomes synchronous with the ADC conversion clock, you wreak havoc on the converter noise - much worse than in #1 - you could start getting downconverted clock noise sweeping in and out of synch with the audio for horrendous effects. Maybe this could happen as a function of storage location, maybe as a function of wear leveling activity, etc.
While I haven't experienced either of the above with audio, I was extrapolating from problems I've had to solve in the past in telecom measurement equipment. It's easy to turn your sampled data system into a spectum analyzer if you're not careful.
So, I'd like to wait and see some noise and distortion numbers between the cards and with the equipment clearly identified. Maybe when you crank the volume all the way up, it is still quiet with this card
Not a huge Sony fan but always had a place in my heart for Trinitron monitors (pro video and PC)
Den