When I record my electric guitar using a high quality domestic cassette tape recorder there is a warbling or flutter, particularly on the high notes played - I cannot hear it by monitoring with headphones whilst recording, only on playback. Seems to happen with other cassette decks also but a little less using my other guitar. Does not happen when recording direct into my computer sound card and recording digitally. Playback of a pre-recorded Shadows tape is ok on the tape recorder. Even happens with the guitar connected directly to the tape recorder. Perhaps a normal feature of the cassette system? Please help before I go and buy a mini disc recorder. I do not need a multi-track recorder but presumably a cassette-based one would have similar problems. I only want to record my guitar along with a CD backing track and have a mixer before it is fed to the tape deck. Can you help as I am a complete beginner at this.