I discovered that I have a minor volume discrepancy/channel imbalance between the left and right channels. Left channel sounds louder/clearer and the right channel sounds quieter. This is causing the music to sound shifted towards the left. I discovered this when bass was hitting harder in the left channel vs the right during an Aphex Twin song that I know.
I thought that I was going crazy (or losing hearing in one ear) until I decided to plug in my solid-state amp and do a mono and stereo test on both my solid-state and Crack amps. Everything sounds fine on my solid-state during the mono and stereo tests, but not when I conduct the test on the Crack. The mono test sounds as if the music is shifted over to the left instead of being in the middle. Stereo also reveals this imbalance. I even flipped my headphones around on my head to make sure I was not imagining this haha.
I should state that the LEDs on the small board of my Speedball do not glow as bright as the LEDs on the large board or the ones at the 9-pin socket. I have not thought much about this because voltages on the large have checked out fine.