AX2 and FCB1010

[Musicmannetje]

I got hold of a very road-worn version of the AX2 amp, and after fixing it up i thought it would be ideal for the rehearsals on tuesday night with the band.. but what about using the stomp boxes and patches in there.

I have a Behringer FCB1010 floorboard with UNO chip (where the top row buttons are assigned as stomp box switches) and want to use that. The PC (program changes) work well via the Midi interface, but what about the box switches. Having read the sysex manual I understand the AX2 needs sysex messages to turn the boxes on or off. The FCB cannot send these out (they skipped that in the last version) and so it came down to using normal CC's (Continuous control messages) as triggers for the stomps. I have build a midi interface on a arduino device I had lying around, waiting for a good project. I build a piece of code that does two things: Send out PC and regular CC commands like they come in, but when a CC is received that is in a specific range, it translates them into a sysex message. Volume and Wah pedals are working just normal (wah is switched on by the 10 button), and using the bottom row of buttons, 90 presets can be selected (18 banks of 5 buttons).

Anyone interested in building this can find my code on github

 

 

[Musicmannetje]

The arduino midi translator device in action:

 

 

[peterjanwilbrink]

Hi musicmannetje,

 

I have an AX2 as well and I was just thinking of building some kind of interface to control the AX2 through an arduino and/or laptop.

I'm curious how you connected and programmed your arduino to send the right midi-codes to the amplifier.

 

would be nice if you want to share your experience

[Musicmannetje]

The setup is actually quite straightforward, if you finally get it (as is with everything, I guess).

The issue is that the AX does react to normal program changes and cc values (for volume and wah pedal, for instance), but in order to switch on the various stomp boxes, one needs to send a sysex string instead of just a cc value. Although I have an FCB with UNO chip (top row can be defined as stomp box switches) the cannot send out a complete sysex. So I have to 'translate' a cc value to a sysex one using the arduino. 

 

I have built a common midi interface for arduino (which is described in various forms all over the arduino forum), with the midi-in going from the floorboard to the arduino and midi-out is connected to the AX2.

 

The code:

As described in the midi implementation chart, there is a way to control the stomps by sending the sysex. After the init string, the data part is expected. The data values of the sysex are three bytes: opcode (0x4 for parameter edit), Parameter number and parameter value. Toggling the value of a stomp parameter between 0 and 1 switches it off or on.

 

The parameter numbers are stated in the sysex chart of the ax212:

 

09H Distortion Box On/Off0/1

19H Drive On/Off 0/1

29H EQ On/Off 0/1

39H Trem/Chorus On/Off 0/1

49H Delay On/Off 0/1

59H Reverb On/Off 0/1 

 

With this, the complete string for (let's say) switching on the delay stomp:

 

F0 Sysex command

00  Line 6 ID msb

01  Line 6 ID mid

0C Line 6 ID lsb

00 AX2 212 ID

04 Opcode for parameter edit

49 Delay switch

01 Switch on

00 LSB value

0F End of sysex command. 

 

Within the code, I have assigned a range of CC numbers that I use to control the stomp boxes. I have defined CCs 32 through 37 to control the stompboxes, and an extra 38 value which controls the parameter 0x32 (50 decimal) to control the WAH switch. In the FCB1010 config I have defined switches 1 through 5 for Distortion, Drive, Modulation, Delay and Wah. The FCB does not have a toe switch on the pedals so I 'lose' one of the stomp switches for wah. 

All other midi messages from the FCB (cc, pc) are going straight through, without translation.

 

The rest of the arduino code is to drive the display showing patch (program) numbers, and commands that are received (cc, stomp switch, pedal values, etc.). This is more because I have a display attached to it, but it works as well without. 

 

I am still busy configuring a JLcooper fadermaster device, so I can use real faders to control the various other settings. This can be handy when building patches.

[peterjanwilbrink]

Misicmannetje, thanks for your message. You inspired me to dive into it and create an interface on an old laptop.

I wrote a little programme in good old visual basic which sends sysex to the AX2.

 

My setup:

Korg NanoKontrol  ->  laptop  <-> AX2

 

laptop is a winxp with MidiOX installed and visual basic.

 

Took me some time to understand the sysex and to get the laptop to send the right sysex code. (fortunately I do have the Line6 midi specification)

The values were somewhat difficult to understand, with the nibbles and all.

 

Now is to decide what I want to controll and I'm ready to go.

I already have the big line6 floorboard with the two pedals and quite a lot of switches, so there already is a lot of things taken care of.

Maybe I could use the wah pedal to controll other functions like chorus depth or speed for example.

 

Do you maybe have any further ideas?

To put it in an arduino could be a next step in the future. However, it could be difficult to connect the Korg nanocontrol to the arduino, considering it is midi over USB... And a nanokontrol needs hands to operate, hands which are already holding a guitar.

 

Then I'd rather build a little floorboard with an arduino and some switches in it. I already have some piano damper pedals lying around and a volume pedal from my GEM WS2 keyboard with a potentiometer in it. Arduino could read the analog value and send the proper midi code to the AX2

[Musicmannetje]

Good to hear you have made some progress.

The FBV longboard (i guess you are talking about that one) is using a kind of midi as well to control the POD's and Vetta amps (at least, that is what I have been told), so I think that will be a good start. Translate the midi messages from the FBV into AX-ready messages. 

Having the pedal change more than just the wah-value can be done, but needs some additional switches, I think, in order to select the function one wants to control. 

I have used a JLCooper fadermaster (programmable midi fader controller) and programmed the sysex messages in there to control the various settings of the AX via faders. That helps a lot to create the patches.