Reduce output

I'm not sure how long you've had this unit but over a period of time speakers being run at high output can lose some of their bite. Have you changed the furnishings in the room concerned. Heavy drapes and softer carpet and furnishings can attenuate your output. Are you playing the same recorded medium? Many CDs are compressed to maximum to please the headbangers whilst others can be natural and completely uncompressed, thereby giving lower volumes on some recordings.

Are you sure the amplifier can breath. No buildup of dust and fluff
on the internals. Bad air circulation can cause heat sensors to attenuate output in some amps too. Are you sure the bass/mid and treble are in their correct positions? Are you sure there's no inbuilt attenuator which may have been pushed in error?

Does your unit have presets such as Rock, Classical, Disco etc? These can cause major output variations. Also many amps have inbuilt graphic equalizers which can be saved. Are you sure someone hasn't used it to cut back cartain frequencies.

If the outputs are protected by fuses, remove then and replace them with new ones. Over a period of time fuses can become stressed due to beinf constantly warmed up and then cooled down. Occasionally ther can appear to the circuitry to be resistors and load the output down.

Apart from these tips maybe a trip to the doctor but before doing so, double check your wiring and connections etc.

Good Luck

BMW

make sure your tape monitor switch is not on.