Hum in one speaker?


Hi, ive been having this hum thats been comming out of my right magnapan speaker. Well first thing is that my whole system is on the right side of the room and the speaker is right next to the equipment but its been like this for years and I never had a hum before. This seems to happen when using the turntable but only with certain albums that have been recorded at a low levels causing me to turn up the pre amp past 12o clock. Recently I put my speakers on mye stands with magic sliders and I dont know if that may have caused an issue or mabey its a bad vaccume tube? I tried moving the speaker around the room didnt seem to do much but the hum seems at its worst at the best listening spot (go figure). Mabey its my cartridge? I dont know but right now my turntable is about 30 inches away from the speaker. The hum is not horrible but when the music gets quiet it can be annoying. I did swap the speakers and with the tweeters on the outside the hum seems to be worse not better.
barruch86
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Sounds like you had some schmutz on your connection. One of the symptoms will be that you will pick up more noise (including hum), and another symptom is that it will be sensitive to vibration (tapping on it makes it cut in and out).

The schmutz causes a high impedance connection, which still can couple in the signal, but the high impedance connection becomes more susceptible to pickup of stray magnetic fields. It's like you created an antenna.

The high impedance connection of the dirt also creates a variable resistor, which changes value under the pressure of vibration. The vibration causes changes in connection impedance and often causes a crackling noise as it changes value. Vibration of the surface the preamp is sitting on becomes modulated into the signal through this variable connection. It is one form of what is commonly called "microphonic noise".

Clean your connectors. I use rubbing alcohol.
Mental ahah yea sometimes I make no sense either lol. Yea its or it was a small hum that came out of the right speaker only when the volume was turned up to a specific level. That level being very loud past 12 o clock. The hum would get stronger the higher up past 12 o clock. I very rarley go up that high but some records are recorded pretty low or I just like the music so much i have the urge to crank it up lol. Anyway it is possible that the interconnect wasnt completely in there and it got pushed in place when I was moving things around. Tom32, wow thats very informative and great idea, ive never cleaned the connectors, im shure my old sp8 is pretty dirty. Again thanks, you guys are the best!
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Sometimes cables fresh from the factory are the worst for schmutz. There can be like this oil stuff on the connector, that is a residue from the manufacturing process.

And what is worst is when you have the oil get from the jack into the socket, because it is harder to clean then. The way to clean that out is to first clean the jack with alcohol, then plug the jack in, jack it in and out, and then clean the jack again. Repeat until you get a solid connection every time you plug in. Your using the clean jack to wipe out the socket.

A totally different topic... if you crank an amp up and the hum gets relatively louder than the music, it can be a sign of having an electrolytic power cap in the power supply going bad. What happens is that the cap is weak, and at high current draw of the amp, the weakness shows up as being significant, but at low volume the cap is able to keep up with the current demand. What was a hefty 4700 uF cap has degraded to a 500 uF cap, and it is not able to smooth out the 60 Hz ripple of the AC power supply when load current demand gets high. There isn't much you can do about a problem like that, the cap will progressively degrade over months or years, and eventually fail altogether. The cap has to be replaced.

If the hum is coming in through the signal path, the relative volume of hum to music volume will remain the same as you crank up the amp.