Well the two are different connections are different internally, as well as externally. You can buy an adapter to switch from one to the other, but I've had mixed results with that method (as far as recording equipment goes...I've never tried it with audio equipment).
If your amp isn't balanced, you're probably better off using the single-ended RCA outputs from the preamp (I assume it has them?) and keeping everything consistent. An adapter probably won't sound better and it may be much worse.
If your amp isn't balanced, you're probably better off using the single-ended RCA outputs from the preamp (I assume it has them?) and keeping everything consistent. An adapter probably won't sound better and it may be much worse.