AFAIK, some tape outputs "might" be buffered, but not the inputs. I could be wrong, but I think that’s how it works.
"If the
tape outputs are buffered, and most aren't, the output impedance of
these outputs is basically the output impedance of the source
components. Often this is significantly higher than the output
impedance of the main preamp outputs. Once again this is not
necessarily a problem, but you may have trouble driving a long cable or a
low impedance load.
"