Transformer near signal lines
Consider just the power input HOT wire. At 1 amp average, or 10 amps peak into the rectifiers, that current peak occurring in 10 microSeconds, how much trash is induced into a 1cm square loop located 10cm away from the HOT wire?

Vinduce = MU0 * MUr * Area/Distance * dI/dT

For air, this becomes

Vinduce = 2e-7 * Area/Distance * dI/dT

and area = 0.01 * 0.01 = 1e-4, distance = 0.1, 
and dI/dT = 10amp/10uS = 1e6amp/sec

Now insert these values into the formula

Vinduce = 2e-7 * 1e-4 / 0.1 * 1e+6 = 2e-7 * e-3 * e+6 = 1e-10+6 = 1e-4

Vinduce = 100 microVolts of 120Hz peak-rectified-current narrow-pulse

And this is just from the HOT wire being 4" (0.1 meter) from your circuit.

How lucky do you feel?

Here is a 3-stage simulation, gain of approx. 1,000 and input of 1milliVolts,
with 60Hz input at 1Million Amp/second slewrate of the 60Hz.

Notice the output SNR is only 4dB, thus the signal is only 1.6x the magnetic interference.