What did my graphs change to measuring when i added in the second signal generator?

[doomvoyage]

Probably the easiest thing i'm over looking or just have inferior knowledge but i'm so confused. As soon as i added the circled signal generator and resistor, the graphs at the bottom changed a huge amount. Everything seems a lot slower.

 

[hevans1944]

You are over-driving the op-amp. Try increasing the value of the 10 Ω resistor and/or decreasing the amplitude of the 500 Hz source.