Taping a phone conversation, part 2

[nancylebov]

When I asked last time, I was told about a thingummy you can get at Radio Shack to send the sound from the phone into a tape recorder. I got one, and it almost works--that is, it records, but so faintly and with so much hiss that the conversation isn't quite audible even with the tape player turned all the way up. I was using 90 minute tape. Should I use noise reduction tape? A new tape recorder? (The one I've got is pretty old.) Something else?