I am digitizing about ten microcassette audio tapes, playing them with the Fisher Model No. PH-M85, the detachable player/recorder part of the Fisher Model No. PHM88. I've been cleaning the heads with S-721H, from American Recorder Technologies. I use a SoundDevices UBSPre2 for digitizing.

Playback of the tapes usually sounds better during a second playback. They may sound even better during a third playback. I've encountered this phenomenon with audio and video tapes in the past, but not as dramatically as with these tapes.

Also, often, levels are decent in one channel, but not the other, and then it switches to vice versa. There doesn't seem to be a problem with the analog cable going from the PH-M85 into the UBSPre2.

Can anybody suggest what is going on?