SWR SM-900 transistor question

[dragracer]

I can still do both.

I figured out how to see the notch and biased both channels.

[J M Fahey]

There have been 3 versions of the SM900, as far as I've seen in our rental inventory. From the front, they all pretty much look the same, but radically different inside.
The 1st image used 2SC3264 NPN's in a quasi-comp design, 2 pairs per channel. The second image used the four pairs of 2SA1295/2SC3264's, though I've seen 2SA1494/2SC3858's used in this one, and the third image used the seven pairs of MJW21193/MJW21194's.

Iīd call that "accomodation to Reality"
You use whatīs available, period, and if "inferior", add as many as needed to keep performance.

Glad they adapted and kept the flagship floating.

No hurry, but it would be interesting to have 3 circuit versions available for side to side comlparison.
Once you *radically* change number of power devices such as here, others things must (should) change too.
Drivers/protection/etc. although they kept basic same cooling tunnel; I guess at least to keep chassis and visuals basically same, once they created a market demand for it.

Personally I try to use always available never faked parts, being "industrial use" doesnīt hurt because itīs a double layer protection: industrial parts have no glamour and either work or explode so fakes are instantly Darwinized.
So I settled long ago on IRFP250 as my power amp building block for anything >150W .
No need to hunt them down on EBay, cheap and plentiful, no need for dubious "equivalents", robust, whatīs not to like?

My old standard was robust and equally unglamorous 2N3773 , until it was practically put out of production. (and then started being faked)

Oh well.