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Spectral preamp picking up a radio station

I have a friend with an all Spectral pre/amp system (25 years old). When I was listening to his system, I can hear quite distinctly  some radio station playing from the left speaker even though there is no radio on in the house. We were playing an album, so it can't be the DAC. This started happening within the past year or two. Could a malfunction in the preamp cause this?
128x128chungjh
middlemass
923 posts
 
You get a tuner for free. What's wrong with that?
jaytor's avatar
jaytor
766 posts
 
The frequency band used for AM is not that high (550Khz to 1720Khz). The Spectral preamps of that age were designed with ultra-wide bandwidth, but I assume had some form of RFI filter on them to prevent this kind of interference. It's possible that a capacitor in this circuitry has gone bad which is now allowing these signals to be picked up and modulated the output signal. 
erik_squires
16,321 posts
 
Spectral is notorious for being "high bandwidth" which also means possibly high noise picked up.

It may also be a function of new interconnects.  Try disconnecting all of them. If that fixes it, consider shielded IC cables.
chungjh's avatar
chungjh OP
265 posts
 
No component has been changed over the past 20 years. It was fine until 1-2 years ago.
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