I have in the past recorded music (6hrs) on vhs tapes. Use the recordings during the day at work. I decided to purchase a good vcr (sony slv-n900) for my recordings. When I record audio with the vcr the playback is not of a steady speed. It goes faster and slower - not much but enough to be annoying. This has happened on 2 nearly new identical units. I have an old Memorex vcr that I used to use for recording that did not do this. What can be the problem? I sure would like some help. Thank You, Tlynn