Plum

Hope you guys can give me some help and I did search but really
didn't come up with much.
I turn on the radio and no sound.
All the stations seem to work and the CD player works fine but
no sound and any place on the volume dial.
I can hear a pop when I turn it off.
Saw a few comments on SC's having an issue like this and they pointed to
an amplifier issue.
Do you think that is my problem?
If so, is the amp part of the radio or separate?
What would I need to replace and approx. cost?
Fuses have been checked and are fine.
Any other suggestions would be appreciated!
Thanks,
Mike