Ok boys, this is what I recieved from the AMC customer service.. Not really as helpful as I would have hoped, but its better then nothing.
Dear Amc Customer,
Thank you for your email!
The cd6b has balanced output and tube output options, while the cd6 does not have any tube function. However both cd players are about the same. The cd6 and cd7 manual is just about the same thing.
Please email us back if you have any questions. Thank you!