The 1k resistors on the left don't need to be there if you have 2 batteries. They waste battery. The same could be said for the ground "amplifier". Hiss is red

The 1k resistors on the left don't need to be there if you have 2 batteries. They waste battery. The same could be said for the ground "amplifier". Hiss is reduced because of the attenuation. It's quite possible a simple resistive pad would be equally effective as the whole thing.