Changing from RCA to balanced- possible?

I've got a Sonic Frontiers Line1 preamp that I really, really like (probably because it's a HUGE step over the Adcom it replaced). It's feeding a Bryston 4BST amp through the balanced outputs, which was another HUGE step for me (I'm relatively new to seperates, and Audiogon). My question is with the preamp inputs- I'm running out of them since the Line1 has only four RCA inputs. It also has two balanced inputs, which I would like to use, but none of my sources have balanced outputs (phono preamp, CD, CD burner, tuner, DVD/TV (sorry!), and reel to reel). Does anyone know if I can change an RCA output to a balanced output, such as through an adapter of some kind, or with a change of cabling? I'm specifically thinking of the phono preamp and tuner, and have considered contacting the respective manufacturers, but I thought I'd throw this out there first. Lastly, this may be a stupid, obvious question to some of you, but it's not to me. Please keep the snide comments to a minimum (or at the least, keep them over my head!) Thanks for any help you can give me. Jim.