My listening tests with both DAC3B outputs used at the same time did not show any problems. I also spoke with Rory Rail at Benchmark on this type of setup and he said a lot of customers have both RCA and XLR connected at the same time.
I tried to have both my RCA and XLR connected at the same time on my Audio Mirror DAC and that was a no go. Even the designer told me that it likely will not work, it did not. The sounds was not good.
I tried to have both my RCA and XLR connected at the same time on my Audio Mirror DAC and that was a no go. Even the designer told me that it likely will not work, it did not. The sounds was not good.