Please help ID output transistors in Crown D150A

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Good day, folks.

I an helping a friend refurb a D150A to use to bi-amp some Kappa 9's. Fresh 'lytics, update the op-amp, replace the carbon resistors with metal film, new and larger filter caps. Just a basic rebuild.

I have been digging on the web and cannot find the transistors that are physically in this amp. I have seen posts that state they are 2N3773 but that does not match either the service manual (2N5631) or what is in the amp. I bet they are service replacements but I cannot find datasheets.

So, if possible, we would like to change them to newer, faster devices and still be stable in circuit. Any and all help appreciated! :up:

2x Motorola 3990
2x (No Mfr.) 3941
Drivers: 4x RCA 3295 (Manual lists 2N3585 NPN)
 
The part numbers on them are Crown part numbers. The channel with 3990 are Motorola 2N5631, the channel with 3941 seem to be some selected Fairchild transistors. I guess this was back in the days of power transistors being exotic, tricky devices.

I wouldn't recommend substituting anything too modern in here - it'll probably just oscillate. OnSemi (Motorola's spinoff company) recommend MJ15015 devices. Maybe MJ15024. I wouldn't risk MJ21194.
 
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