I actually use both XLR and RCA on the DAC3B to 2 different preamps (or integrated amps). At least until a few days ago and I now only have 1 preamp left, the HPA4. Next week I will again have 2 preamps and the RCA output on the DAC3B will be hooked up to the second preamp.
I also use the Benchmark gear in the recommended configuration with the 24 dBu+ signal. The RCA is considered the poor cousin in terms of connectivity by Benchmark. They strongly recommend XLR throughout.
https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces
I know you were asking about connecting to a amp. I the HGC has both RCA and XLR outputs so you could have both of your amps connected to the HGC at the same time.
I strongly recommend you try the LA4 or HPA4 in the chain for FREE with the 30 day home trial. I thought it was a big deal to put the preamp into the chain. I have owned DAC2 HGC, DAC3 HGC, and DAC1. The very best sound is with either of those 2 preamps in the chain.
I also use the Benchmark gear in the recommended configuration with the 24 dBu+ signal. The RCA is considered the poor cousin in terms of connectivity by Benchmark. They strongly recommend XLR throughout.
https://benchmarkmedia.com/blogs/application_notes/balanced-vs-unbalanced-analog-interfaces
I know you were asking about connecting to a amp. I the HGC has both RCA and XLR outputs so you could have both of your amps connected to the HGC at the same time.
I strongly recommend you try the LA4 or HPA4 in the chain for FREE with the 30 day home trial. I thought it was a big deal to put the preamp into the chain. I have owned DAC2 HGC, DAC3 HGC, and DAC1. The very best sound is with either of those 2 preamps in the chain.