7f33ac1a_ecp_cc__Value_Notes
[Part] C1L, C1R [Size/#] 15mm or axial [Value/Notes] 
These are the coupling caps. There is spacing for a 15mm box type cap (such as a Wima) but there are also extra pads to use other larger caps. Something in the 0.22uF to 0.47uF range is probably sufficient. If you want to use smaller values, you may need to increase the value of the R4's.
ecp.cc
Value/Notes