Soundstream Rubicon 555 repair

i'm not sure i know what you mean by too high rail voltages...are you talking about the output stage supply rail?

what makes you think it's 25% too high?  this voltage is regulated by the bridge rectifiers and when they go as a rule they go...they dont go up in voltage and to have both of them go at the same time in the same way seems a little to weird to be realistic.....   describe your actual problem... what is this amp doing or not doing?  not what you suspect what may be wrong.....

By rail voltages I"m talking about the two supply rails after the bridge diodes.  This is a 5-ch amp and one supply rail is for the front 4 channels and the second (higher voltage) is for the sub channel.  I have a schematic of the power supply and it specifies the front channels rail should be +/-22V and the sub channel rail should be +/-33V.  When I turn on the amp I am measuring +/-28V and +/-46V respectively.

If you are experienced or knowledgeable in car amp repair, can I email you the schematic and discuss more specifics ?

Any help would be greatly appreciated.

these voltages are based on a reference input voltage...is your input voltage a regulated 14.4 Volts?

again, what exactly is this unit doing or not doing?  blowing fuses, no output, etc, etc.

I am using a regulated DC power supply (12.5V) to power the amp.

Originally a FET which activated the overheat circuitry failed, but after replacing it the amp turned on fine.

The unit amplifies sound just fine.   All the channels work, but I am concerned that running the amp with the power rails with too high voltage may cause components to fail in a short time.  The unit is not blowing fuses, and the output is fine.