Where is the final coupling cap on this layout Thunderchief layout from GGG

[rosssurf]

. I am interested in doing mods to my Thunderchief seen here. One of the mods is to "adjust the value of the final coupling cap to add or subtract more lows" Can someone tell me where this cap is on the following layout from GGG.
http://www.generalguitargadgets.com/pdf/ggg_thunderchief.pdf

[Ardric]

That would be the 0.015uF (15nF) cap.  After the last JFET, before the low-pass filter and volume control.  Larger values let more bass out.

[rosssurf]

Great thanks for your help!

Now if I can only get it to stop whistling at me at high gain settings.