Ambika troubleshooting thread (intermittent midi sent to vc)

Sorry if this is overstepping as a newbie, thought it might be convinient to have one thread for people to work through their ambika issues. Create a central location for common mistakes/tips/solutions.

Anyway, I’ve built the motherboard, tested well no problems. Today built 2 smr4 voicecards and installed them. They sound perfect… when the notes play. I’ve got a real strange intermittent note bug. The unit is receiving midi notes fine (the note displays) however it chooses not to play most of the notes for some time. Eg can play C,E,Bb perfectly for a while (and in polyphony), all other notes don’t play. Then after a few seconds the selection of notes that sound changes and C etc are silent.

I’m not sure where to begin looking… I set a sequence to ascend through each of the 12 notes in an octave, relative to the key pressed. Each key triggered the sequence, so midi data IS bring recieved, however only a handful of notes (and often not the root key pressed) actually sound.
I played a note and ran through the oscillator range, and that worked fine for sounding every note.

To me the problem seems to be the motherboard is accepting midi data correctly, but not passing it on to the voicecards. What has me confused is how certain notes can be played, on both voicecards, but others won’t sound. Given that its a problem affecting both voicecards I’m calling the mobo the culprit.

Anyway thoughts/opinions would be appreciated :slight_smile: ill redo the firmware tomorrow to see if that helps anything.

Which voicecards are assigned to part 1?

To me it simply looks like part 1 is assigned more voicecards than installed, so the notes are sometimes sent to voicecards which are not installed.

@jimi23 This is rather similar to what’s happening with my newly built Ambika and a single SMR card. I’ve set my sequencer to output a rising chromatic scale starting with C but I’m only getting every few notes played. I’ll search the manual to see whether this is because the single part is being sent to more than the single voicecard installed.

By default, Ambika assumes it is loaded with 3 voicecards ; so all notes are allocated over voicecard 1 ; voicecard 3 ; and voicecard 5. You need to go to the voicecard allocation page and indicate that part 1 is played by voicecard 1 (if you have only one voicecard installed) ; or by voicecard 1 & 3 [or voicecard 1 & 2] if you have two voicecards installed.

Check the voice allocation section of the manual.

@jimi23 Yes, as Olivier says, it’s because the part is split between multiple voicecards. If you press s5, you’ll see that it’s set in poly mode on power-up. Change it to mono mode and all the notes should play on the single voicecard.

@pichenettes Thanks for another brilliant design. It’s amazingly reassuring to build something and get it working first time and I think this is all down to your superb designs, clear PCB layout and excellent instructions. Joyeux Noël!

@pichenettes When Ambika stops receiving MIDI data the voice allocation switches back to poly mode. What’s the trick to keep mono mode allocated?

@pichenettes I’ve worked that out now by reading the manual!