What do op-amps do in Integrated amps?

[cafad]

Hi everyone,
First post here and it is the reason I found the htguide just yesterday. I'm hoping someone out there more experienced in the audiophilia way can give me an answer (google is pretty slack about questions that don't involve movies or celebrities). What is the function of the op-amp in an integrated amplifier?
Now let me explain why I ask, replacing the op-amps in a cd player can result in a fair change to the sonic performance of said player and these op-amps are available for a few bucks so if you are after a small change to a player you are "almost" happy with then this is a good (and not particularly expensive) direction to investigate.
I recently discovered that my integrated also has an op-amp, (I have no electrical or instrument experience so I am assuming that all integrated amps have them, feel free to correct me if I'm wrong) so can I change out this op-amp chip and (for a small number of $$) change the sonic performance of my amp? And of course, if I can and do, would the change be large enough to notice?

Cheers Everyone!!
Cafad.

[mjb]

It obviously depends on the circuit design, but op-amps are generally used as buffers with unity gain. There are some threads here where people have exchanged them in certain amps and noticed an improvement, but I'd do some serious research before trying this yourself!

[Kal Rubinson]

Opamps can be used for many purposes including unity-gain buffers, line drivers, input buffers, VCAs, offset nulling amps, etc. The best type of opamp to be used would different for each of the applications.

Will a swap be noticeable? Depending on the opamp chosen, it may not work at all. Random swaps are not recommended.

Kal

[cafad]

OK, looks like I have a lot more to learn about IC layout and function. Back to the books for me.
Thanks for the prompt reply guys, it is greatly appreciated.

Cheers,
Cafad.

[cafad]

Just for the record, after downloading data sheets on about a dozen op amps and consulting with an electrician and instrument tech I switched out my burr brown op amp with an analog devices chip (similar specs, same circuit layout)and the amp ran just fine. However, also for the record, I couldn't hear any difference in the end product. I may try again at a later date but for now my curiosity is sated.

Cheers,
Cafad.

[mjb]

Burr-Brown (now Texas Instruments) might have the edge, but the differences are problably very subtle - as you've found. The BB OPA-2604 is supposed to sound very very good though, many people use this as a replacement and rave about it. Google finds lots of threads on this, perhaps you've read some of them already.
Cheers!