Anybody know what can be done about stray capacitance on the MCK input of the Crystal CS8405A. I am now attributing the intermittent output of the board to the 11.2896 MHz input from the Empeg. It seems to get loaded down with capacitance while the S/PDIF board is installed inside the Empeg. It will not work reliably inside the Empeg. If I grip the wire (the insulated portion) carrying the 11.2896 MHz signal it basically kills the output of the board. There are no shorts. Right now I am using one conductor of a 3M color coded ribbon cable about 6 inches long. I tried some shielded audio interconnect cable, but it wouldn't work at all with this cable. Do I need low capacitance shielded cable? Perhaps twisted pair? Throw me some suggestions here.

Stu

You probably need at the least a line driver on the Empeg board and possibly a receiver to recover the clock signal. A 74HCT244 should do the trick. This could be used to buffer some of the other signals too. Maybe just shortening the clock cable to the absolute minimum would do the trick. I assume the input capacitance of the CS8405A is about 8pF or so maybe.

You could also AC couple the clock signal and bias it on the receiving end with a couple high value resistors to 1.4V. This may not work well though as I don't think the input is a schmitt trigger type.

Speedy

Thanks for the suggestions. I was just hoping to avoid more circuitry. I've got a 74HCT541 I could give a try though. I can't really shorten the leads, as they have to be long enough to reach the back of the Empeg for the SMT version of the board I have planned. I'll try the buffer and maybe some twisted pair. Hopefully I won't need a receiver, that will be a whole nother headache to deal with.

Stu