Split your guitar signal into two discrete signals by using a mixer. Use a 1/4-inch guitar unbalanced guitar cable to connect the signal out jack of your guitar to the "Signal In" jack of a mixer. Connect two unbalanced 1/4-inch guitar cables of exactly the same length to the 1/4-inch output jacks of your mixer.
Connect one of the discrete signals coming from your mixer to one of your pre-amps. Plug the cable coming from your mixer into the "Input" jack of your pre-amp. Adjust the timbre of the signal by removing the bass and mid-range frequencies and applying gain or distortion, as desired.
Connect the other discrete signal coming from your mixer to one of your other pre-amps. Plug the cable coming from your mixer into the "Input" jack of your pre-amp. Adjust the timbre of the signal by removing high-end frequencies and amping up the low and mid-range frequencies. Apply gain or distortion as desired.
Combine the signals from your two pre-amps in a stereo stack with two 1/4-inch unbalanced guitar cables of equal length. Connect the signal out of your pre-amps to the "Stereo-In" jacks of your stack, ignoring left and right channel data.
Create a balanced mix of the two guitar signals by adjusting the volume on the two pre-amps. When you subtract high-end or low-end frequencies of a signal, you change the volume of that signal. Adjusting the volume knobs of each pre-amp until the final combined signal equally features both your guitar tones creates a unique and sonorous tone.