Christopher
The Russian transistors that I got on eBay were rated for much less than 150 milliwatts, which is very low and prone to thermal runaway (which is what causes the originals to go bad). Plus you are supposed to match the pair for equal base to emitter Vbe voltages.
It’s so much better and cheaper to use PNP silicon transistors. They sound better, more resistant to thermal runaway, and are two for ten cents. I don’t bother to match them for Vbe. One thing I haven’t tried yet is to make a heatsink for them. I would take a 2″ or 50mm length of heavy bare copper house wire. Then flatten it out with a hammer. Then wrap each end around each transistor and glue it in place. This will thermally couple the two transistors and help stabilize them. This is optional, not mandatory.
