Adding to the colleagues above i want to stress the importance of the following characteristics for operational amplifiers for audio peramplification:

The first parameter for any amplifier is  its noise, the input equivalent noise must be small enough to be acceptable for the overall performance of the amplifier.

The second important factor is the total harmonic distortion which measures the nonlinearties of the amplifier. It concerns the fidelity of the amplifier. The amplifier must  not generate nonlinear distortion products except in an acceptable level.

For the level of noise + distortion please refer to fig.17 of the data sheet of Texas instrument brought by you in the question.

The third factor is the required gain. It must give sufficient gain  with flat response on the whole audio frequency range.  

The power supply ripples must be sufficiently rejected to avoid its effects on the audio signal.

Best wishes

This is not a simple question. One has to follow each parameter and decide if it's enough for his particular application :-)

As you are working with microphone preamplifier,  so I believe  mostly you would be dealing with low frequency signals.  The performance of amplifiers are mostly applications dependent.  As such in your case for preamplifiers a gain of 20-30 dB are generally sufficient.  But the major factors would be the noise and total harmonic distortion. Power dissipation is also an important factor.  But for comparative analysis mostly the noise efficiency figures , which are dependant on current consumption,  input noise are widely used by researchers.

Hope this would be helpful for you.  You can study works on microphone preamplifier by Dingkun Du for better insight 

Adding to the colleagues above i want to stress the importance of the following characteristics for operational amplifiers for audio peramplification:

The first parameter for any amplifier is  its noise, the input equivalent noise must be small enough to be acceptable for the overall performance of the amplifier.

The second important factor is the total harmonic distortion which measures the nonlinearties of the amplifier. It concerns the fidelity of the amplifier. The amplifier must  not generate nonlinear distortion products except in an acceptable level.

For the level of noise + distortion please refer to fig.17 of the data sheet of Texas instrument brought by you in the question.

The third factor is the required gain. It must give sufficient gain  with flat response on the whole audio frequency range.  

The power supply ripples must be sufficiently rejected to avoid its effects on the audio signal.

Best wishes

Thanks a lot for all of your answers. Im collecting audio opamps datasheets to compare data and apply what you mentioned,

Would your lecturer allow you to substitute a Field Effect Transistor for the generic Op-amp? That will certainly bring costs down.

Hello Ian:

It is possible. You think I could "make" those opamps with transistors instead?

The INA217 is certainly great, but there have been decent preamps prior 2002. Thus I'd look for some 'old' but 'proven good' preamp design - e.g. using some FET. Not as simple to use as the INA (which is some sort of 'no-brainer), but with comparable performance.

Yes! Op amps are generic and can do all sorts of functions. They are an overkill for your application. 

Thank you so much for your info. I´m mixed this with some info I got from an amplifier designer here and I´m finally understanding more about this. I think this weekend I´m finish my theoretical frame.

Hello!

I contacted one of my music and electronics teacher here and helped me a lot understanding how to understand and apply your suggestions. I´m starting to write about all this in order to organize ideas, and considering that the shipping is taking longer than expected, I´m asking for components here to make a first prototype.