What are these parts

[billybeer]

I got a pair of custom amp that my uncle built. I am trying to figure out what the outputs are but have not been able to figure it out what they are. They are TO-3 case. They have printing and p/n that look like this.
4 4
571134 561049
7917 7917

there are four of each per channel. Does anyone know what they are and what can be used as replacement? I have tried to crossreference them but can find nothing.

any help appreciated,

Thanks,

Bill

 

[Netlist]

TO3

571134 = 2SK134
561049 = 2SJ49
Both are Mosfets

7917 is date of manufacturing: Week 17 year 1979
the 4 = ?
Anyone: correct me if i'm wrong..

Hugo