Building the ultimate DIY power amp

[wg_ski]

Originally posted by K-amps


Thats good info...however I have poor memory but for some reason the 250watt figure also comes to mind... thereby made me not think of the 1302/3281's... any thoughts on that?

K-

The 250W rating comes from the fact that Tj(max) of the TO-3 cased devices is 200C, not 150C as in the flatpacks. R(th) is comparable.

The most likely scenario is that 1302/3281 dies were used, in TO-3 cases with larger (or multiple) bond wires to allow a higher current rating. Most dies can be selected for higher Vceo, so a 250V or more rating is not out of line. If you buy enough of them they'll put them in any package you want, and for a price will do any testing and grading within reason.