There are two crystals, 11.2896 for 44.1 and 12.288 for 48. You can unsolder the crystal and inject an external clock to the pad that is the input to the gate. The crystal is connected to a CMOS gate, one side an output pin and one to an output pin. Trace the crystal connections on the board to the chip, look up the part number and get the datasheet. Then figure out which pad of the crystal connects to an input pin of the chip. The external clock goes to this pad.
You could just inject 11.2896 and leave 12.288 alone, that way you get the synched clock for 44.1 files but can still isten to 48KHz internet radio etc. Since you are not interested in the jitter from the output you can just use a simple twisted pair from the external DAC to the SBR, try and keep it as short as possible. Another option is to use coax and a line driver in the DAC and a terminated resistance in the SBR. This gives much better clock waveform in the SBR, but for your application its not really necessary. I've done this with an SB3, but connected to the internal I2S signals instead of using the S/PDIF output. At first I just used a piece of ribbon cable which worked quite well, but radiates all kinds of EMI. Then I switched to using LVDS which uses much lower voltage levels so it doesn't radiate nearly as much. Of course that meant a little board in the SB3 which had the LVDS receivers and transmitters. It actually works very well. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=63147 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
