My schematic app on my Android phone, has it's limitations, as to what it will allow me to do. It's a free app. I can not simulate a.c. circuits with the free app, only d.c. circuits.

 

So the supply is not a battery?

 

It can be a battery, but most people like using a.c. to d.c. adapters.

 

Is the signal from the guitar going to this circuit first?

 

Another option to eliminate power supply noise is to install a 1uf cap across the 120K resistor. Then connect a 50 to 100K resistor from that junction to pin3 input.

 

If using effects pedals, this preamp should be at the end of the chain.

 

See

View attachment 338157

View attachment 338158

I took your advice and redrew my schematic, to show more details.

 

One comment is that the 741 opamp design is very old. Much better and more stable op-amps are available that are also more reliable. And have the same pin-out. And are much less noisy.

 

The TL081 or TL071 would work. Both are jfet input op amps, have low noise, and fast slew rate.