Your amp came out in 1996 so it is max 15 years old. Call the company and see how old it is by serial number, that will give you a date for age. Tell them what has happened and they should be able to tell you in the ball park.
Depending on where it blew, if something blew, yes it could affect both channels, especially if it happened in the preamp section. Do you have another amp or preamp to stick in the circuit? How long have you had it? Something is not getting the gain it needs but if turned up high enough the signal comes through to the level you want.
Depending on where it blew, if something blew, yes it could affect both channels, especially if it happened in the preamp section. Do you have another amp or preamp to stick in the circuit? How long have you had it? Something is not getting the gain it needs but if turned up high enough the signal comes through to the level you want.