I hate to say it, but this is a common problem is the audio equipment has poor RFI rejection.
There is this design aspect known as a 'stopping' resistor, that is used in tube and solid state circuits to prevent oscillation, and also has a big effect on susceptibility to RFI.
The resistor is in series with the signal and is placed as close as possible to the input connection of each amplifying device (grid of a tube, gate of a MOSFET and so on).
The resistor interacts with the input capacitance of the device, preventing it from causing oscillation by acting as a low pass filter. This is effect of RFI for the same reason.
The thing is, many audio designers don't employ stopping resistors (the Japanese really didn't use them at all for several decades) so you run into problems like this if you have heavy RF sources nearby and otherwise poor grounding.
The 'I hate to say it' part is you may have to change out gear to something more stable to get rid of this. May.
What happens if you operate your cell phone close to your stereo? Do you get interference?
There is this design aspect known as a 'stopping' resistor, that is used in tube and solid state circuits to prevent oscillation, and also has a big effect on susceptibility to RFI.
The resistor is in series with the signal and is placed as close as possible to the input connection of each amplifying device (grid of a tube, gate of a MOSFET and so on).
The resistor interacts with the input capacitance of the device, preventing it from causing oscillation by acting as a low pass filter. This is effect of RFI for the same reason.
The thing is, many audio designers don't employ stopping resistors (the Japanese really didn't use them at all for several decades) so you run into problems like this if you have heavy RF sources nearby and otherwise poor grounding.
The 'I hate to say it' part is you may have to change out gear to something more stable to get rid of this. May.
What happens if you operate your cell phone close to your stereo? Do you get interference?