parnass@ihuxz.ATT.COM (Bob Parnass, AJ9S) (02/21/89)
Put aside the 60 Hz filter idea for the moment. Rather than poor power supply filtering, it sounds like your hum problem may be due to: 1. a ground loop or 2. an open shield in the patch cables connecting the recorder to the receiver. I assume the receiver is powered by 120 VAC, although your article didn't specify. If it is indeed a ground loop problem, it could be solved by breaking the ground connection at one end of each patch cable. Since I have to do this when connecting my monophonic Panasonic recorder to some scanner radios, but not others, I constructed 2 different patch cables. One cable has shield connections at both ends, and the other cable is a shield connection at only one end. If, instead, the problem is an open shield, then repair or replace the cable(s). In article <2313@rayssdb.ray.com>, iws@rayssdb.ray.com (Ihor W. Slabicky) writes: >I use a portable stereo cassette recorder to record music off my >receiver. When the recorder is powered from the AC line, I can hear >lots of 60 Hz being recorded on the tape. Moving the recorder, cables, >or power cord around tends to lessen the hum. When I record using the >batteries, no hum. Also, when I playback, if I put the INPUT switch >on the recorder to the MIC position, no or very little 60 Hz hum is >heard, but when the INPUT switch is set to LINE, lots of hum. Ideas? -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Bob Parnass AJ9S, AT&T Bell Laboratories - att!ihuxz!parnass - (312)979-5414