You don't usually need any diodes on a macro keyboard. Diodes are only needed where you have "shift", "ctrl" type keys which would be pressed at the same time as another key. On a QWERTY keyboard, diodes are needed because during high-speed typing, the next key might get pressed before the previous key has been released. On a musical keyboard, the diodes are needed because playing chords means that multiple keys are pressed at once. For a macro keyboard, usually only one key is pressed at once, so no diodes are needed.