I know that the main BulkyMIDI-32 has a fancy display that shows instruments and so on, the original Roland MT-32 also did something similar back when they were still sold in music shops. However, I wanted an excuse to add a ton of LEDs to the project while having a bit of fun with older logic chips. Because, who doesn't want more blinking lights? Noone, that's who. My starting point was an article by W. Dunczewski, titled MIDI Channel Monitor that was printed in the october 1993 issue of Elektor Electronics.
While the low-level description of the circuit details is better left to the article itself, I'll only make a brave attempt at describing what it actually aims to accomplish; The purpose of the board is to light up an LED corresponding to each MIDI-channel, but instead of doing it as yet another Arduino-based design - it implements this using using basic logic chips and counters. It does this by waiting for a digital MIDI-message, then picks out the bits that specifies the channel.