| PHilgeman |
With my all of my equippent that runs through a 6 channel VCA based volume control, I get terrible clicks and pops when flourescent lights and fans are turned on and especially off. I have a EFI filtered IEC jack at the input, and a rather large two-pole AC line fitler that I made myself. Adding the latter did not do anything. Do you have any suggestions on what might stop this besides turning everything on and off before/after I listen?
The VCA's have a standard torroidal regulated power supply. The gainclones run off of a standard transformer/rectifier/caps power supply.
Thanks,
Paul Hilgeman |
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| roadkill |
Make sure the EMI filter case is making contact with the metal of the amplifier chassis. Also use the shortest possible ground lead from the IEC connector to the amp chassis.
However, the source of your problem is more likely to be interference through the inputs. Many seem to like to use differential amplifiers at the input, causing a perforation in the faraday cage formed by the chassis, through which the EFI picked up by the interconnect will radiate into the amplifier. This works both at the input and at the output. A Crystal Semiconductor appnote suggests the use of 1nF capacitors at the output, whose grounded ends connect direct to the chassis.
Another likely source is from, well, your source. Maybe it doesn't have adequate EMI filtering.
To see if the source is due to radiated or conducted emission, you can use a GSM cell phone as a good source of radiated energy. They produce pulsed RF, causing a distinctive sound in any susceptible equipment. |
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| PHilgeman |
Sorry if I was unclear, it is not a radiated interference. It is pulses/peaks/drops that come through the mains line or ground..
-Paul Hilgeman |
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| BrianGT |
I used to have problems with my old desk lamp. I ran an extension cord to a different outlet for the lamp, and the problem went away.
--
Brian |
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| PHilgeman |
This is sortof a whole-appartment problem. It happens with teh flourescent light in the kitchen, the exhaust fan in the bathroom, and the ceiling fan above our bed.
-Paul Hilgeman |
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