SD-CARD player
Posted: 14 Sep 2009, 07:22
o chestie faina.ce se presupune transportul perfect in cazul CD-urilor Audio 16/44
citirea facandu-se de pe card SDHC are multe avantaje fata de un transport CD-obisnuit :
-complet silentios neavand piese in miscare
-citirea e bit-perfect de fiecare data (se extrag track-urile din CD-urile audio cu EAC direct pe cardul SD)
-nu introduce jittere aditionale datorita clockului ultra low jitter
-pe langa iesiri ordinare Spdif are I2S direct pe placa fiind compatibil a-l lega de DAC -ul preferat...pretul e ft ft bun
http://cgi.ebay.com/QA-550-Hi-End-WAV-D ... 911.c0.m14" onclick="window.open(this.href);return false;
iar un proiect DIY facut de EC Design care ii prezinta toate avantajele,denumindu-l the ultimate source
"The advantage over CD players is the bit-perfect CD image, stored on a semiconductor memory card, that's able to reproduce exactly the same digital audio data, over and over again. Unlike CD players, the semiconductor memory is insensitive to shocks and vibrations, the card is also more robust compared to a CD that damages (scratches) easily. The SD-card player is absolutely silent (no moving parts).
The SD-card capacity also allows storage of multiple CDs or even an entire play-list. Due to the clock strategy and interface (I2S out), very low clock jitter and interference levels could be obtained. The interface / interlink related problems are eliminated.
The advantage over computer (PC) based digital audio sources is the absolute silent operation, low power consumption, very low interference levels, very low jitter, and The interface / interlink related problems are eliminated.
All conventional digital audio sources, interlinks and digital audio receivers add noise, interference, and jitter signatures to the sample timing signal. This is mainly periodic jitter (worst kind). This jitter is extremely difficult to attenuate, and unless the design is absolutely perfect, jitter always finds a "back door" and pollutes the entire DAC electronics like a virus. This interference spreads though wiring, components, PCB, and wireless (EM radiation). Slaving transport or sound card helps, but it won't prevent jitter from spreading among the DAC electronics as we still require the external data signal that also contains jitter.
The problem is even worse when using external DACs. Interlink, digital audio receiver interference, and jitter are added.
The easiest way of solving this problem is to create a clean digital audio source, and integrate it with the DAC chip using I2S. That's exactly what we did with the SD-player.
How will this compare to a CD player or computer? well, it would have far lower jitter and interference levels to start with, because a lot of potential jitter and interference sources are taken out of the equation. The jitter signature can be shaped much easier, obtaining mainly random jitter.
So when the digital audio sources are constructed optimally, the SD-player concept is most likely to provide best results. "
poza cu el finalizat : http://i32.tinypic.com/2ckkn6.jpg" onclick="window.open(this.href);return false;
(topic initial http://www.diyaudio.com/forums/showthread.php?t=140538" onclick="window.open(this.href);return false;)
citirea facandu-se de pe card SDHC are multe avantaje fata de un transport CD-obisnuit :
-complet silentios neavand piese in miscare
-citirea e bit-perfect de fiecare data (se extrag track-urile din CD-urile audio cu EAC direct pe cardul SD)
-nu introduce jittere aditionale datorita clockului ultra low jitter
-pe langa iesiri ordinare Spdif are I2S direct pe placa fiind compatibil a-l lega de DAC -ul preferat...pretul e ft ft bun
http://cgi.ebay.com/QA-550-Hi-End-WAV-D ... 911.c0.m14" onclick="window.open(this.href);return false;
iar un proiect DIY facut de EC Design care ii prezinta toate avantajele,denumindu-l the ultimate source
"The advantage over CD players is the bit-perfect CD image, stored on a semiconductor memory card, that's able to reproduce exactly the same digital audio data, over and over again. Unlike CD players, the semiconductor memory is insensitive to shocks and vibrations, the card is also more robust compared to a CD that damages (scratches) easily. The SD-card player is absolutely silent (no moving parts).
The SD-card capacity also allows storage of multiple CDs or even an entire play-list. Due to the clock strategy and interface (I2S out), very low clock jitter and interference levels could be obtained. The interface / interlink related problems are eliminated.
The advantage over computer (PC) based digital audio sources is the absolute silent operation, low power consumption, very low interference levels, very low jitter, and The interface / interlink related problems are eliminated.
All conventional digital audio sources, interlinks and digital audio receivers add noise, interference, and jitter signatures to the sample timing signal. This is mainly periodic jitter (worst kind). This jitter is extremely difficult to attenuate, and unless the design is absolutely perfect, jitter always finds a "back door" and pollutes the entire DAC electronics like a virus. This interference spreads though wiring, components, PCB, and wireless (EM radiation). Slaving transport or sound card helps, but it won't prevent jitter from spreading among the DAC electronics as we still require the external data signal that also contains jitter.
The problem is even worse when using external DACs. Interlink, digital audio receiver interference, and jitter are added.
The easiest way of solving this problem is to create a clean digital audio source, and integrate it with the DAC chip using I2S. That's exactly what we did with the SD-player.
How will this compare to a CD player or computer? well, it would have far lower jitter and interference levels to start with, because a lot of potential jitter and interference sources are taken out of the equation. The jitter signature can be shaped much easier, obtaining mainly random jitter.
So when the digital audio sources are constructed optimally, the SD-player concept is most likely to provide best results. "
poza cu el finalizat : http://i32.tinypic.com/2ckkn6.jpg" onclick="window.open(this.href);return false;
(topic initial http://www.diyaudio.com/forums/showthread.php?t=140538" onclick="window.open(this.href);return false;)