I was looking at doing the same thing and wanted to get a preamp that had dual outputs. There is a thread I created that discusses this. It turned out some preamps such as the Mola Mola Tambaqui, Wyred 4 Sound, Atmassphere and a host of others support this. I connected the manufacturers to see if it was OK to use the preamps this way.
You connect both amps to the preamp at the same time. You would turn the amp you want to use on and the one not required off. I was planning on have 2 sets of speakers in the same room.
In the end I decided to get the preamp with the best headphone section and not the dual outputs. The new plan is to manually flip the XLR’s from one amp the other when I want to hear a particular speaker.
You connect both amps to the preamp at the same time. You would turn the amp you want to use on and the one not required off. I was planning on have 2 sets of speakers in the same room.
In the end I decided to get the preamp with the best headphone section and not the dual outputs. The new plan is to manually flip the XLR’s from one amp the other when I want to hear a particular speaker.