Zen Amp - why blocking cap at input and output?

[sonidos]

I picked up a mini zen pcb from a fellow member of the forum last month. It is based on the schematic found here:

HeadWize - Project: The Zen Headphone Amplifier by Marcello Pellerano

Why is a blocking cap needed on the input and then on the output? Wouldn't the caps on the output suffice and I could just jumper the coupling cap at the input?😕

 

[sawreyrw]

If you don't use the input cap, this will upset the DC bias of Q2.

 

[sonidos]

Glad I asked! Thanks!

Heck, that makes sense now that I look at more closely. Duh.