I'm currently looking into the mechanism of redstone in minecraft. For one circuit, I need an instant repeater, and reading Minecraft wiki, the smallest one so far is the 4x5x3 instant repeater by sethbling.
Experimenting a bit, I found the attached circuit to repeat instantly as well (both noteboxes activate at the same time, at least more synced compared to a one tick delay introduced by a repeater).
Is there any fault with this circuit? I am suprised that I couldn't find this solution googling for instant repeaters as its even more compact (3x3x2).