MIDI CC changes send my GM on a wild ride...

I've been happily using my GM36/FMS 432 MKIII/Ctrlr app for a few years, all with no issues. I recently picked up a Helix LT and tried to use it as a midi controller. Changing presets is no problem but the Ctrlr app doesn't play well without the FMS, which is irritating but I can live with. I started fooling around with setting up CC messages for changing boost and channel settings and found a weird issue. I can toggle CC messages for turning on/off the boost feature, and send a CC message for choosing the clean channel with no issues. As soon as I send the same CC message for changing channels (CC 31) with the range over 31, the GM 36 goes haywire, flipping relays and bouncing off the wall. I did a bit of MIDI sniffing and see that the amp/Ctrlr/FMS use Sysex messages while the Helix sends plain old PC/CC messages. Before I go nuts trying to figure this out, has anyone experienced anything similar and know what I'm doing wrong?

Thanks in advance.

You certainly have part of the answer in your own post.  The GM36 and the other H&K MIDI amps run via the apps need SYSEX enabled hardware.  There has always been a problem with using the H&K setup with cheap Chinese knockoff MIDI controllers for this very issue.  Their input/output buffers are not large enough to hold anything other than the standard MIDI packet sizes.  I would guess you probably are experiencing a similar issue though it won't be the cause of whole problem.

I'm absolutely no MIDI expert but the crazy behaviour of the amp makes me a little nervous.  Are there any options in the Helix to alter things like packet structures?

Looking at the Helix LT manual on page 59 it says:

Helix LT Manual wrote:MIDI CC Helix LT has reserved specific MIDI CC messages for global functions; these CCs cannot be used as controllers. If you attempt to learn a CC message reserved for global functions (see "Controller Assign"), the following dialog appears:  "Learn Parameter Controller;  This MIDI CC# is reserved for global functions!"

MIDI CC# Value Function

Pedal and Footswitch Assignments
1 0-127 Emulates EXP 1 Pedal
2 0-127 Emulates EXP 2 Pedal
49 0-127 Emulates Stomp footswitch mode's FS1
50 0-127 Emulates Stomp footswitch mode's FS2
51 0-127 Emulates Stomp footswitch mode's FS3
52 0-127 Emulates Stomp footswitch mode's FS4
53 0-127 Emulates Stomp footswitch mode's FS5
54 0-127 Emulates Stomp footswitch mode's FS7
55 0-127 Emulates Stomp footswitch mode's FS8
56 0-127 Emulates Stomp footswitch mode's FS9
57 0-127 Emulates Stomp footswitch mode's FS10
58 0-127 Emulates Stomp footswitch mode's FS11
59 0-127 Emulates EXP Toe switch

Looper Controls
60
0-63: Overdub;
64-127: Record Looper Record/Overdub switch (FS8)
61 0-63: Stop;
64-127: Play Looper Play/Stop switch (FS9)
62 64-127 Looper Play Once switch (FS3)
63 64-127 Looper Undo switch (FS2)
65 0-63: Forward;
64-127: Reverse Looper Forward/Reverse switch (FS11)
60

MIDI CC# Value Function
66 0-63: Full;
64-127: Half Looper Full/Half Speed switch (FS10)
67 0-63: Off;
64-127: On
Looper block on/off (if available); also enters/exits
Looper footswitch mode
Additional Controls
0 0-7 Bank MSB
32 0-7 Bank LSB—Setlist select
64 64-127 Tap Tempo
68 0-127 Tuner screen on/off
69 0-7 Snapshot select
70 0-127

Additional global MIDI commands (reserved for future
use)
71 0-127
72 0-127
73 0-127
74 0-127
75 0-127
76 0-127

128 0-63: Oh;
64-127: Nooo   Helix LT achieves self-awareness and starts poking fun of that face you make during the solo

I wonder if any of these reserved messages are conflicting with what the H&K setup needs to see.  Anyone out there know more about MIDI message structure to be able to see whether this is the problem?

Hmmm! Looking a little more at the Helix manual you can see that it is also capable of being used for interfacing digital audio, and the Command Centre section from Page 47 looks pretty comprehensive with a sharp learning curve. How familiar are you with that proces on the Helix? It looks very possible that it is just down to settings within this sort of area.

Thanks for the reply Bordenbert! I think the reserved CC messages with the Helix are for received MIDI. Using the controller functions (pg 47 of Helix manual) I successfully programmed CC 64 to toggle the boost on and off when sent from Helix footswitch to the HK. This worked without issue, which leads me to believe that I can't train the Helix to respond to any reserved CC messages but can send any as an output, since CC 64 to Helix controls tap tempo. When I tried the same with CC 31, which isn't reserved for anything on the Helix, my HK goes nuts. I would expect that since the HK manual indicates I can use CC messages and says nothing about Sysex that I would have no problem. PC messages work fine, changing presets with no problem. I routed my MIDI cables every which way, and can actually change the Helix preset by changing channels from the Ctrlr app, but after my amp went crazy, I decided not to try anything else until I could figure this out. I was really afraid that the relay for changing from clean to dirty channels was fried after the way it was flipping.

I'll have to setup my MIDI sniffer and capture the different messages as sent from Ctrlr/HK/FSM and then the Helix. My first pass (which I didn't save) clearly showed the extended data set for Sysex, whereas the Helix only sent a few bytes of data. There may be something about the structure of the CC message from the Helix the HK doesn't like.

On the positive side, I have the 4 channel method set up with the Helix and HK, with the HK going through a Two Notes Torpedo studio and into my audio interface, and this setup rocks. Since the Helix can process two independent signal chains from one source, I have stereo Guitar->Helix->HK->Torpedo into my Motu as one stereo signal path, and then I have the second Helix signal path setup as a different simulated amp/cabinet going direct to my DAW. The tonal options are unlimited, and I can drive any kind of simulated signal and re-amp as needed. I'm totally digging the Helix. This issue with the MIDI control has been the only downside.