Hi Wayne, first off you need to find out what the frequency from the Big Ben really is. Is it a word clock or a master clock? A word clock would be 44.1KHz (or 88.2), but the master clock is 11.2896. If the clock from the big ben is something other than 11.2896 you cannot directly feed it into the SB.
The next thing to know is the voltage and impedance level. The SB takes a 3.3V CMOS level signal, you need to find out if the signal from the big ben is compatible. Its almost certainly some form of impedance controlled transmission line interface, probably either 50 or 75 ohms. You need to know the voltage level of the clock, if its 5volts its too high, you will need to add an attenuator, if its 3.3V, all you need is a termination resistor, if its less than 3.3V it gets more complicated because you then need some form of amplifier to get it up to 3.3V. I just looked at the Big Ben spec sheet and its 75 ohms, but it doesn't specify the voltage level. You either need to get that from Apogee or maybe someone else that knows the answer can chime in. So you are going to need a 75 ohm BNC connector and at least 1 maybe two resistors for the simple case. Make absolutely SURE you have a 75 ohm BNC, most BNCs out there are 50 ohm, this will compromise the clock. How and where you mount the connector and how you get the signal from the connector to the board are going to be important. Since the SB does not have a metal case you will have to run a ground to the connector as well as the "signal". Probably the best way to do this is with a short piece of 75 ohm coax from the connector to the board. At the board you will have your 1 or two resistors. Alternatively you could just use a "pigtail", a short piece of coax coming out of the box with a cable mount female connector rather than a mounted BNC jack. This would be easier to implement and actually probably work better. Once you find out the voltage level we can go over the details. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=24800 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
