Opamp for Mic preamp

[-_nando-_]

Hi there!

I'm about to design a microphone pre-amp based on a typical "3 amp instrumentation amplifier". Cost is a big concern. For an input impedance of 600Ohms, which opamp would be quieter, the NE5532 or TL072?

Thanx!

 

[simon7000]

5532 would be quieter but will pick up RFI.

 

[-_nando-_]

Well, I use to put a ferrite bead and capacitors at the input, I think that it can fix the RFI problem. I'm more concerned about which one has better CMRR and is more silent using a low impedance at the input. Any ideas and opinions are welcome!

 

[SY]

Hi there!

I'm about to design a microphone pre-amp based on a typical "3 amp instrumentation amplifier". Cost is a big concern. For an input impedance of 600Ohms, which opamp would be quieter, the NE5532 or TL072?

Thanx!

An SSM2019 or THAT1512 is still pretty cheap and will perform enormously better.

 

[Michael Bean]

Ne5532 is the best choice of the two. But SYs suggestion is better than either.

Mike

 

[-_nando-_]

An SSM2019 or THAT1512 is still pretty cheap and will perform enormously better.

In which terms you mean? Noise only? Because these specific chips are nothing more than the typical 3-amp configuration, but of course, with laser trimmed resistors. I think I can get away with the NE5532 + 0.01% resistors and it will be better than many mic pre-amps out there... 🙄

 

[SY]

Noise, distortion, common-mode rejection. And no need for 0.01% resistors- the internal matching and thermal tracking is better than you can do with discrete (unless you want to get super exotic and expensive).

 

[stellavox]

I've just finished a THAT1510 design and can say that it sounds wonderful. PLUS, their website has a number of great application notes about the intricacies of mike pre designs - keeping high CMRR; balanced / unbalanced operation; phantom power; etc.

Charles