pcjg7045@uxa.cso.uiuc.edu (Pramod Charles John) (11/29/90)
I am having trouble with my integrated amplifier. It seems to be pick- ing up a local radio station in one channel. It is at an extremely low level, and can only be detected at very low levels or with headphones etc, with no signal. I would appreciate it if someone would give me some info as to how I could eliminate this problem. Sincerely, Pramod John e-mail Pramod@uxa.cso.uiuc.edu Thanks!!
hgw@julia.math.ucla.edu (Harold Wong) (11/30/90)
In article <1990Nov29.053422.17859@ux1.cso.uiuc.edu> pcjg7045@uxa.cso.uiuc.edu (Pramod Charles John) writes: > > I am having trouble with my integrated amplifier. It seems to be pick- ing up a local radio station in one channel. It is at an extremely low level, and can only be detected at very low levels or with headphones etc, with no signal. I would appreciate > it if someone would give me some info as to how I could eliminate this problem. I had the same proble but with a Hi-Fi stereo VCR. It was picking up a nearby radio station on the right channel and it was loud. I turned the VCR 90 degrees and it fixed the problem. Now I have the VCR pointing perpendicular to the TV. Not a pretty sight but it works. At first I thought it might be the antenna wire but I pulled ALL the wires out (except for the power cord) and used a headphone to monitor it, and the problem was till there. Anybody have any better ideas? I'l like to turn the VCR back facing the the same direction as the tv. Harold ------------------------------------------------------------------------------- Harold Wong (213) 825-9040 UCLA-Mathnet; 3915F MSA; 405 Hilgard Ave.; Los Angeles, CA 90024-1555 ARPA: hgw@math.ucla.edu BITNET: hgw%math.ucla.edu@INTERBIT
kenw@col.hp.com (Ken Wyatt) (12/01/90)
It is possible for audio amplifiers to "pick up" strong radio stations
via their speaker leads (long leads make great antennas). The rf energy
then becomes coupled into the input stages of the preamp circuitry. Try
connecting a 0.01 uF ceramic capacitor (50 volt rating, or higher) across
each speaker wire as shown. These may be purchased at Radio Shack.
_______ _______
| | | |
| |---------------------------------| |
| AMP | | |SPKR |
| | O 0.01 uF | |
| | | | |
| |---------------------------------| |
| | | |
------- -------
Also, you might be try winding two or three turns of the speaker
cable around a ferrite torroid core or rod material. This will tend
to "choke off" the rf from the cable.
If neither of these ideas work, the rf may be coming in via some other
piece of equipment. Try unplugging the audio patch cords of each piece
of equipment one at a time, while listening on the headphones. For
example, occasionally rf energy may enter a system via the pickup wiring
of your turntable. These are the wires that connect the pickup cartridge
and travel through the arm into the base of the turntable. A couple of
0.01 uF ceramic capacitors across each channel pair (install these in the
turntable base, not the tone arm) may solve the problem.kenw@col.hp.com (Ken Wyatt) (12/05/90)
Your vcr <could> be picking up the rfi via its power cord. Try winding a few turns (of the cord) around a ferrite rod or torroid core. Locate this ferrite near the entry point of the vcr. ------------------------------------------------------------------------- | Ken Wyatt | HPDesk: Ken Wyatt / HP0800 | | Product Regulations Mngr | UNIX: kenw@hpcol.hp.com | | HP/Colorado Springs Div. | FAX: (719) 590-7679 | | PO Box 2197 | CompuServe: 75665,1727 | | Colorado Springs, CO 80901 | Amateur Radio: WA6TTY | | (719) 590-2852 | -- Space for rent -- | -------------------------------------------------------------------------