Slim Phatty to Ultranova - no sound

Hiya peeps.. so i have a slim phatty and want to use my ultranova’s keys to play…

I’ve the audio out the phatty into the nova.. then midi back out the nova into the phatty but this doesnt seem to be working (was informed by the shop i bought from that this is how to do it but obviously not)
im pretty new to hardware so any help on this would be hugely appreciated..

thankyou

j

I have both too. Have you enabled MIDI out in the Ultranova’s “Global” menu?