These need not be NP0 or C0G, but would be great if you have them.
A good quality multi-layer monolithic ceramic cap will be fine.
Just need to have low series inductance.
I like to use X7R tempco when I have them on hand, but have used lesser caps with no ill results.
---In PHSNA@..., <mendiola_loyola@...> wrote :
What kind of capacitor should I use for AC coupling?In the schematic ac coupling capacitors are C5 and C8.
Alfredo Mendiola Loyola