Here is a plot of what SPICE predicts the frequency response will be for the preamplifier stage in the 1176. The low frequency rise is most likely due to my inaccurate modeling of the source impedance by not taking the transformer secondary impedance into consideration.
It could also be the feedback network not having enough feedback at low frequencies. Anyways, I don't really care because the only thing that matters is how it responds in the real world. I will compare this with real test results after I run it on an Audio Precision. Stay tuned!