There would be no effect whatsoever,beyond extending the signal path unnecessarily.Bring the Line Level signal out of the back of cassette player (Tape Out) to audio input on back of computer.I use an RCA at cassette end to Stereo mini plug input on Computer end.Do not use headphone jack as it is amplified.Input signal to computer must be Line Level.Otherwise you will introduce distortion.Tape Out is Line Level.Use it.