/diy/ - Do It Yourself

After looking at various schematics of opamp input stages, I managed to come up with my version of the amplifier stage. I managed to sort of match the frequency response, as well as input and output impedances. Once in the circuit, the freq response curve is exactly the same, although with the opamp it's about 8dB louder.
In the original circuit, varying the gain also changes the bias of the jfet as well as the low end response, which I could not accomplish with my rudimentary knowledge. I do get some clipping with the opamp at higher gain as with the original circuit, but it's not the same. I can post pictures of my simulations