I have a Sanyo broadcast quality vhs editor that has all kinds of neat
audio functions.
It's a s-vhs machine with 4 channel stereo options.(instead of
tracking down video signal it can burn down four fm audio channels
with better specs than cd audio. 105 dbs dynamic range vs 90 for cd
and signal to noise and w&f unmeasurable.)

And your VCR also has the inherent 60 Hz switchpoint noise, even with the audio
signals replacing the video, you will still get the switchpoint noise because
of how the helical scan system for any VCR works.

This is one of the main reasons why AFM on videotape, regardless of format and
perceived quality, is never considered ideal for audio recording.

http://www.faqs.org/faqs/AudioFAQ/part7/

Scroll down to section 14.18 for a good explanation why VHS and Beta hi-fi
aren't so hot for serious audio recording.

I'd rather stick with digital, thank you very much. - Reinhart