A quick and dirty solution might be something like this
http://www.sweetwater.com/store/detail/Phantom2Pro/But you still need to unbalance your signal.
You might make a post in Microphones and ask about powering options for the Byers - I think there a few guys around who know the power requirements and the best practice for getting an unbalanced signal from them.
I would suggest giving normal bias tapes a try - and use noise reduction.
I did some experiments a few months ago with Dolby C and normal bias tapes - and was amazed how good the result was.
Also - if you have the capability/gear - just remaster anything you record to digital right away...no point in the extra wear and tear on the recorder - and you'll get the best transfer possible.