Operational amplifier TL081 used for Audio?

OBW0549

Joined Mar 2, 2015
3,107
Can we use the TL081 integrated circuit as a microphone amplifier?
Of course you can use it; just about ANY operational amplifier can be used as a microphone amplifier, given an appropriate circuit and appropriate power supply voltages. The only question is, how well will it perform and will the resulting amplifier meet your requirements. Any part you choose, TL081 or otherwise, will have its strengths and its weaknesses, and it may or may not meet your needs.

What is your power supply voltage? If you look on the TL081 data sheet you'll see that the recommended minimum supply voltage is ± 5 volts, so if you want something that will operate off a single +5V supply this chip will not work. If you have at least ± 5 volts available, it might suffice.

Another factor that might influence the suitability of the TL081 is that it is rather noisy, especially at low frequencies (see Figure 17 on page 12 of the data sheet). So if your inputs signal is very low in amplitude, such as from a dynamic mic, and you need a very high-fidelity output from your amplifier free of background noise, the TL081 might not be a very good choice.

So the bottom line is yes, you can use it; but you need to look at the specs to see whether you should.
 

MisterBill2

Joined Jan 23, 2018
4,620
Summarizing other comments, and adding my own opinion, certainly the TL081 will function as a microphone amplifier. I do not understand why you would add two additional stages after the amplifier , as shown in post #5, since the gain can be as much as you choose. The TL071 series does offer a lower noise voltage and if the system will have much low frequency response then that would be a better choice. As for needing a bipolar power supply, it is a simple matter to provide a mid-supply reference voltage for the inputs, and run the device from a single supply of 10 volts, or a 9 volt battery if battery power is used.
 

Thread Starter

DonutChan

Joined Mar 3, 2019
32
Summarizing other comments, and adding my own opinion, certainly the TL081 will function as a microphone amplifier. I do not understand why you would add two additional stages after the amplifier , as shown in post #5, since the gain can be as much as you choose. The TL071 series does offer a lower noise voltage and if the system will have much low frequency response then that would be a better choice. As for needing a bipolar power supply, it is a simple matter to provide a mid-supply reference voltage for the inputs, and run the device from a single supply of 10 volts, or a 9 volt battery if battery power is used.
The two additional stages are to convert the sine signal to a square one.. i'm not sure how i can wire TL081 along with the components before it and whether i should add anything else. Also, the power voltage is 5V as shown in the picture, (9V going through a regulator)
 

brockrwood

Joined Oct 23, 2016
47
From what I learnt by reading Audioguru's post in many different forums, a better one is the TL072 (selected by its better (lower noise) figures.
Make sure you get a real, not counterfeit, TL072 if you try it. I bought a batch of counterfeit TL072’s on ebay not knowing they were fakes. The performance of the fakes was not as good as a real TL072. Buy from a reputable source.
 

OBW0549

Joined Mar 2, 2015
3,107
Make sure you get a real, not counterfeit, TL072 if you try it. I bought a batch of counterfeit TL072’s on ebay not knowing they were fakes. The performance of the fakes was not as good as a real TL072. Buy from a reputable source.
The TS has only a single +5V supply available, and the TL07x series has the same minimum supply voltage requirements as the TL08x series: +/- 5V minimum, so it would not work for him.
 

brockrwood

Joined Oct 23, 2016
47
The TS has only a single +5V supply available, and the TL07x series has the same minimum supply voltage requirements as the TL08x series: +/- 5V minimum, so it would not work for him.
How about TI TLC272? The TLC272C is supposed to go down to only 3V minimum supply voltage.
 

OBW0549

Joined Mar 2, 2015
3,107
How about TI TLC272? The TLC272C is supposed to go down to only 3V minimum supply voltage.
It would function, though it is quite noisy at low frequencies (see data sheet, Figure 37 on page 28). It might suffice for your application, although I certainly wouldn't want to use it in a demanding audio application with a dynamic mic having a low output voltage.
 
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