Has anyone ever found a reasonably priced source for output fets in a Sony XM-2252HX ??? i know the original mitsubishi parts are very pricey last i checked. anyone know of a reliable substitute. i'll post the original part number when i get a chance.
The 36P15 can't handle as much current but it should survive. It really depends on how abusive the owner is.
The low voltage transistor probably wouldn't survive. The amp is supposed to have ±55v on the rails in high voltage mode. The output configuration (cascode) will divide the voltage across the outputs but it will not divide it evenly so one of the P-channel outputs will almost certainly see more than its rated voltage.
I'd be interested in seeing the guts of an old, original FS70 that was installed by sony and one of the ebay transistors. Many times, the ebay versions of hard-to-find transistors are low quality parts that work reasonably well but cannot handle the full power/current of the originals. Generally,, the silicone die is much smaller. Sometimes there are multiple smaller dies to help boost the current capacity.
Something I didn't notice earlier is that the original is a 4v drive. The standard FET requires a higher drive (10v is commonly used). The 4v drive circuit may need to be modified to use with other FETs.