Seadogs1, if the preamp is internally balanced, you should be able to get an output from the preamp by driving pin 2 and pin 1, and also by driving *pin 3* and pin 1 (pin 1 being ground). If it is unresponsive on one of those inputs, say pin 3 for example, then the preamp has the connector for convenience only.
The exception would be if the preamp employs and input transformer, but such use is rare in high end audio, although it would not surprise me in the least to see some products that use them. As a result, if in doubt check with the manufacturer.
The exception would be if the preamp employs and input transformer, but such use is rare in high end audio, although it would not surprise me in the least to see some products that use them. As a result, if in doubt check with the manufacturer.