Are you sure the noise is on the original tape? Because too often it is simply added during the transfer. If that is the case, check if the VCR that you are using for playback is connected with the tv signal. If so, unhook it for the conversion process.
If the noise is on the original tape however I would recommend recording everything onto your PC, then separate the audio stream from the video using TMPGEnc or something similar, then you can easily remove the static noise with SEKDs Samplitude.

Hope it helps.
Cheers.