Hi, I have a receiver with mono output (shortwave RX) and I want to connect it to the stereo input of the sound blaster but also isolate the two systems. The classic way is to do it using an 600R:600R isolation transformer.
However I have seen this schematic https://antiqueradio.org/art/iPodAdaptorSchematic.jpg from this page https://antiqueradio.org/iPodAdaptor.htm it is intended for the othr way round, to accept stereo input and convert it to mono.
However I thought if this phasing of the transformers could be used to isolate the two sound blaster channels.
If the stereo input of the sound blaster has a sufficiently high impedance, simply use 2 high-ohmic series resistors for each stereo input. Say 10..30% of the input impedance.