Transistor subbing issues

[gonzothegreat]

I was linksurfing the counterfeit transistor issue and I found somebody who said modern transistor subs for the outputs on an Altec 9440a (RCA 120392, Mot 120226/120157) suck compared to modern replacements. That seems at odds with the guy who replaced all the outputs on his Mc2100 with 2n3773 devices and loved the sound.

I thought that as long as the various rating for a transistor were roughly the same or better as the sub, you were fine. EW suggests replacing balanced inputs with newer devices to improve DC offset issues.

[SolderIron]

Depends on what he means by sucks. Sound effect? reliabiltiy? Does he know enough to select a proper subsitute? A transistor spec sheet is more than 2 pages. Though for audio only a few parameters are meaningful.
Does he know how to properly adjust the amp after replacement? does his amp has other bad/out of spec parts?

I am a firm believer that semi technology is better than old. Sometimes too good. new devices have higher bandwidth that in some circuits they will response faster or oscillate.

[EchoWars]

I found somebody who said modern transistor subs for the outputs on an Altec 9440a (RCA 120392, Mot 120226/120157) suck compared to modern replacements. Opinions are like assholes...everybody's got one...

The transistors made in the 70's cannot compare with those made today. The equipment, cleanliness of the Fab's, and the processes have undergone radical changes since those days.

The only downside is that the selection of discrete devices is a lot smaller today than it was then.