How I Rack-mounted my Line 6 Pod Guitar Effects Processor

Step 4 Creating a MIDI-thru

One of the things I never liked about the Pod was the fact that although it has a MIDI-IN and MIDI-OUT, there is no hardwired MIDI-thru port... I decided to fix this... On the existing PCB, the MIDI-IN port goes into a GN138 opto-isolator - what more perfect place to patch a MIDI-thru port onto then the output of the opto-isolator! One thing though is that to properly implement a MIDI-thru there should be a very light buffer delay - rather than using a dedicated buffer IC, I decided to get a cheap inverter (the 74HC14 - technically a Hex Schmitt-Trigger Inverter - like 22 cents each) and send the signal through two of the inverters (essentially negating the inversion) which causes a slight delay / buffer effect... then using a 220 ohm resistor to ensure to slightly limit the current on going out the line. By the way, you should be able to re-use this circuit on almost anything that you want to add a MIDI-thru port to - as long as you have a +5V connection, proper ground, and can get at a good, isolated signal from the MIDI-IN.

(BTW - this circuit works perfectly! I've not have any sync errors or speed delays patching through this MIDI-thru)