opamps on audigy 2 .. which to replace?
Aug 27, 2003 at 5:57 AM Thread Starter Post #1 of 10


Mar 22, 2003
I want to replace the line out 1 and line out 2 (front, rear) opamps from the audigy 2, but I have no idea which they are. There are three types of opamps (I believe) on the board: three that are labeled 4558C, another, upside down compared to the others, the 33078, and the last one also upside-down, 79L05A.

Which two do I replace? Any help would be great.

pic 1

pic 2
Aug 27, 2003 at 3:08 PM Post #2 of 10
I had this card for a while just for testing purposes, it has those 4558 and even 4556 - they are all big piece of <censored>
even worse than any 5532
79L05 is just a 5V regulator and I don't know anything about that 33078.. I took a detailed photos of the output pcb on Audigy2 - will post later..

it's here:
Aug 27, 2003 at 3:51 PM Post #3 of 10
so, njm4556a is basicaly high current version of njm4558

njm4556: dual - 3V/us - 8 MHz - 70mA output
njm4558: dual - 1V/us (!) - 3 MHz (!) - lower mA
mc33078: dual - 7V/us - 16MHz - 29mA

these are horrible specs
but it seems like they are able to operate from relatively low voltages..

I suppose that the 4556 opamp is used for front channels as a buffer in order to be able to drive some headphones and from it's position I believe that the 4558 next to 4556 is the LPF for it.. and that 33078 is most probably the mike preamp.. there is no need for input LPF since this is done internally in the Sigmatel codec.. you must figure out what is the rear channels opamp yourself by tracking the path from the output jack or using multimeter

edit: 33078 specs added
Aug 27, 2003 at 8:21 PM Post #4 of 10
Damn I don't want to break out a multimeter, etc.

My eyes aren't good enough to find those traces, either.

Anyway, which 4558 should I be replacing for the front line out buffer then?

Thanks again, btw
Aug 29, 2003 at 6:06 AM Post #5 of 10
OK, yesterday I attended my friend - owner of Audigy2 and also of the soldering station and of course I had some opamps in my pocket
so it turns out that 4556A is for front channels and 4558C on right side of it is the one for rear channels. I've tried only two opamps - AD8620 and OP275 - both does improve the sound significantly, but AD8620 was who shines the most
I'm begining to think that anywhere you put it, it rules
So my advice for you is to go with it on all channels - it finaly made a soundcard off the Creative
Jun 1, 2009 at 5:37 PM Post #9 of 10

Originally posted by tortie
Hey guys, where do your buy your ad8620 opamps?

heh, that's a nice question
how about sample program on Analog's website, huh?

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