I have now seen a copy of the relevant IR electrical input circuit for the NAD C 356BEE. This consists of a simple demodulator, to remove the 38kHz carrier, with a pull-down of 330ohm.
The SB output is only just over 3V, driven by an HC4066 (CH74HC4066), which has an output impedance which is not defined at that voltage, but I guess could be >200ohm. The output is quite capable of driving an IR LED through a 220ohm resistor with sufficient power that the NAD amp optical IR input responds appropriately. My guess is that this is simply too low an input impedance for the output from the SB3. So, I think I need to build a pre-amp between the SB3 and the NAD to lower the impedance. I wonder if I can power this from the RS232 port. +-------------------------------------------------------------------+ |Filename: NAD_C256BEE_IRin-small.jpeg | |Download: http://forums.slimdevices.com/attachment.php?attachmentid=11439| +-------------------------------------------------------------------+ -- awy ------------------------------------------------------------------------ awy's Profile: http://forums.slimdevices.com/member.php?userid=7480 View this thread: http://forums.slimdevices.com/showthread.php?t=39397 _______________________________________________ plugins mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/plugins
