I am trying to create a audio amplifier that runs from a single supply. fundamentally i need to create a high gain amplifier of around 1900 Av with a bandwidth of 400 to 400KHz with a defined input impedance of 50K and i have to use 741 op amps the inpout signal is around 1mV-10mV.

Ive decided to create a LPF with one op amp and then connect it to a HPF through another opamp, which will give me the gain and bandwith.

as the signal coming in is +/- 1mv i want to create a 5V DC bias that the signal will ride on. however i'm struggling to get the amplifier to work.. i have attached two photos.one showing the amplifier with the non inverting pin ground, this gives a output signal of around 0.2V with the negative part of the signal clipping which is what i expect. when i set a dc voltage of 5V on the non inverting pin i get a flat response?

for the time being i have left of the Cap on the feedback resistor which would create the LPF.

 

have a look at the app note page 6.....http://www.ti.com/ww/en/bobpease/assets/AN-31.pdf

 

Hint: You are starting with the wrong op-amp. Check out the app note Dodgydave recommends.

 

At 400KHz, the 741 has an open loop gain of 2.5. It is totally useless for what you are doing.

And why would a audio amplifier go up to 400KHz anyway?

Bob

 

I was working on that yesterday. I came up with, "You will need 76 chips to do this". Then I doubted myself and erased it.

Thanks for being more succinct than I could manage that day.