which op amp should I use in audio circuit and why?

[Hywel]

I'm simulating a circuit in multisim for the first time. My aim is to build a bass preamp so I have a few designs that require op-amps in order to not only cut but boost the signals harmonic content at certain frequencies.

The problem is that all the designs I've found have a variety of op-amps (1C1a - TL072, U1a, U1b, 1C2b - TL072, BF245, TL072, etc) inside but no reason as to why. And I'm also a little confused as to how to power them. I have an LT1013MJ and an LT1013MJ8 in my circuit atm. I've tried powering them a variety of ways but none seem to work.

So please, any advice on which op-amps to use with unbalanced audio and how to power them would be greatly appreciated!

Thanks - Hywel.

[KostasB]

Hi Hywel

Audio applications typically require low noise, good quality amplifiers like the LM833. The LM833 amplifier is described as a dual audio operational amplifier in Multisim.

I created a circuit that uses two of the LM833's to boost the 8KHz harmonics and attenuate the rest(band pass filter). If you want to boost different harmonics, adjust the resistors and capacitors values according to circuit theory.

To power your amplifiers in Multisim, you should better use the Vee, Vdd sources as they are references that stay constant throughout the circuit. The attached example uses Vdd=12V and Vee=-12V to power the positive and

negative op-amp rails respectively. To locate them in Multisim, go to Place>Component and from the Master Database go to Sources>Vdd. After you place it down, double-click on it and set its nominal value.

Let me know if that helped.

KostasB

NI UK Applications Engineering

Message Edited by KostasB on 03-20-2008 11:16 AM