I could not make it work (yet) - any advice ?
Checklist:
+ loopsynth v2

+ v1.xxx.118

+ mellotron directory and many subdirs

+ .wav in the directories
+ mellotron directory on the SD card (checked twice)
+ 16-bit or less samples (VLC says so) - by the way, I am using
https://sonicbloom.net/en/free-sb-mellotron-samples/ more precisely the Flute MK2 [attached]
+ Arturia Keystep 32, output midi channel 1, midi cable OK (tested elsewhere) connected to the DIN-TRS adapter (tried two of them, type A)
+ load channel 221 - seems OK (steady RDY yellow LED)
+ some signal seems to be coming in (kind of a small blue light led SIG is blinking)
+ volume B4 at high level (tested on channel 1)
-- no sound

Of course, this might be difficult to debug... but anyone can see what could be missing ? E.g. Midi Channel number ; should I "tune" something on the Loopsynth to get the Keystep 32 recognized further? I used it to define a chord progression, seems to work fine.
Gilbert