Does anybody know if the following MIDI DIN connectors will fit in a breadboard?
(or in general with 'generic' electrical components?)
And the same for:
Diodes to be used for MIDI in.
Breadboards use a 2.54 mm (0.1") grid. The PCB footprint on that link uses a nominal 2.5 mm grid, which is essentially the same:
However, those pins are rather large; it's possible that you need to rotate some pins by 90° (with pliers and brute force) to make them fit into your breaboard's holes, or that they do not fit at all. And even if they fit, they can ruin your breadboard. You might need to file them off.
Consider using a panel-mount MIDI jack instead (which would require soldering, or leads with test clips):
(search for "5 pin DIN female jack")
The MIDI specification recommends a 1N914 diode, but that is only because it was written over thirty years ago. The 1N4148 is much more common now, and has the same characteristics. But this diode is used only as reverse voltage protection for the optocoupler's LED, so you can use any random fast switching diode.
As for the optocopler (which you didn't mention, but I'll throw in my two cents worth anyway): the PC900 was discontinued, and the 6N138 is slow. Use either the H11L1 (of which the PC900 was a clone) or the 6N137; both work best with a 1 kΩ pull-up resistor.