Hi Swamp,
I am pretty sure that this is the way it goes. When you select CD, it takes that input and sends a signal both to the amp section and to the tape out RCAs. In your setup, when you select input 2, it is looking for a line level source signal, but you only have your SBAM output to it, thus nothing is being sent to the tape out RCAs in the back of the unit. It is truly not a tape loop like that of the Joule Electra preamps and others, it is simply a tape out and will only output IF you have selected the input with an actual signal going to it.
Bobby will probably explain it better.
I am pretty sure that this is the way it goes. When you select CD, it takes that input and sends a signal both to the amp section and to the tape out RCAs. In your setup, when you select input 2, it is looking for a line level source signal, but you only have your SBAM output to it, thus nothing is being sent to the tape out RCAs in the back of the unit. It is truly not a tape loop like that of the Joule Electra preamps and others, it is simply a tape out and will only output IF you have selected the input with an actual signal going to it.
Bobby will probably explain it better.