what is this op amp used for ?

[mmaghakian]

I just got a Denon DRA-550 receiver from the thrift store. looking for ways to upgrade it
I notice that there is a 4558 OP AMP but not sure if it is even in the audio path. it looks like it might be a switch. can someone smarter than me tell me the purpose of this 4558

thanks !

 

[JMFahey]

Show us more, WAY more, 90% of its connections go outside the image.

Upload the full schematic/service manual.

 

[mmaghakian]

here is the service manual, it is not for the USA version but my receiver does have this 4558

 

[PRR]

Even in your snippet, the inputs both come from a 100uFd cap, so is surely not audio. It is reading supply current of the IF chip. Which suggests it reads signal strength.

 

[geoffw1]

Even in your snippet, the inputs both come from a 100uFd cap, so is surely not audio. It is reading supply current of the IF chip. Which suggests it reads signal strength.

Looking at your snippet and the full service manual, the 4558 takes input from TP1 and TP2. The block diagram shows a signal strength meter associated with these two test points. This concurs with the previous comment from PRR. If the 4558 is working, there's nothing to be gained from "upgrading" it, any general purpose opamp would be fine there.

 

[mmaghakian]

thank you to all for verifying my suspicion I will not concern myself with upgrading it