"Michael A. Terrell" wrote:
Eeyore wrote:
Arny Krueger wrote:
According to my friend, RCA tried various ruses to come up with enough
40411-type devices, but could never equal their original product. He sold a
ton of amps that were not durable and was forced out of business.
Eventually, he started cutting open devices, both old and new, and found
results similar to what we've seen far more recently with counterfeit
transistors.. It was his opinion that RCA was sort of counterfeiting their
own product.
Seen that with the RCA410 too which they sold as replacement MJ410s. It took
thumbscrews to get them to admit they contained dies from 3 seperate lines. A
bright tech noticed by the way that there were 3 'hard codes' stamped on the
case and 2 of them gave trouble.
The 410s were just used as fastish drivers, we were using the 2N3773 by then as
main output devices. Seemed solid enough. If they'd been around at the time,
they might have saved your friend's company.
I used a lot of 2N3773 to replace 40411, and some other 100 volt
transistors. I think I still have one pair left in stock. 
Oh and the 3773 had a 140V rating with correspondingly larger SOA IIRC.
Modern MJ1502Xs make it look silly now but it was THE high power audio output device
of the day.
Graham