Florian probably has a better idea but just looking at the circuit you could feed an external signal through a 1uf/16v (or higher) cap into the junction of R7, R8, R9 & C5 on the chorus board. It may need some level adjusting though.

Murray

On 11/12/2011 5:41 p.m., foraxx wrote:

 

Has anyone done a chorus input mod on the JX-3P? Florian's page ( http://fa.utfs.org/diy/jx3p/jx3p_mod.htm ) describes adding an extra stereo out for the chorus. Would it be possible to have a synth signal direct output normalled to a chorus input which then feeds the main stereo out?