Marshall JVM410HJS Midi problem

algiman

Member
I'm having problems changing the channel on my JVM using the FX8's midi. Sometimes the channel will change, sometime it doesn't and I need to select the same preset several times before the amp responds. Any suggestions? I've double checked the amp using a different midi controller and it works fine, so the FX8 is the problem here. If this is just a quirk of the FX8 it'll be a real shame as it is brilliant, but not being able to rely on it to change the amp channel makes it unusable for me.
 
My JVM works flawless with the FX8... I don't use the MID block but I only use a Program Change in the config tab of the first scene of every preset, works perfect.

That's what I'm doing too, it's just not working reliably. I'm beginning to think the FX8 may have an actual fault.
 
Already discounted the cable - both by swapping it out, and by using the same cable with a Rocktron All Access midi controller. However, a bit of an update:
The JVM channel switching works with the Rocktron, but is intermittent with the FX8, leading me to think the FX8 was the problem, but, I've just tried the FX8 with a Marshall 6100 and it worked fine, so there seems to be some issue confined to the combination of the JVM410HJS and the FX8. Weird. I'll contact Marshall too, but any other suggestions would be welcome.
 
Have you tried switching the PC change setting to off in the settings of the FX8 ? It's in the MIDI section.
 
Just tried, no difference.

Do you send only PC to JS? I can remember that I had similar problem when I tried to send PC and CC at the same time. JS ("older" chip version in JS works only with either PC or CC commands; I read somewhere that there is a newer chip version that allowed to mix the both statements).

Here I will try to explain the thing a bit better :) on example with midi mate:
* I wanted to programm midi mate to have 5 patches in the lower row and 5 switches in the upper row
* lower row ie 1: clean green, 2: crunch orange, 3: crunch red, 4: od1 orange, 5: od2 red+master2
* upper row: 6: fx loop on/off, 7: master1/2, 8: noisegate on/off etc.
* in this case, midi mate send PC for channel change but also all CC-messages (fx loop, master, noisegate)
* JS does not like it
 
Very strange. Have you tried using an actual midi block in addition to just the scene change midi function as an experiment? I wonder if the midi block could interfere with the scene midi setting somehow? Might be worth making sure only one at a time is set up.
 
It works perfectly on my Hughes and Kettner amps ...

Are you sure you aren't accidentally programming and reprogramming the JVM each time you send the the message ?

I just checked the manual and it looks like you are doing exactly this - press program - send the midi message - send the message again to switch out of programming mode.

After doing channel 1 try selecting a different channel on the JVM then select channel 1 via the fx8 - looks to me like you keep reprogramming the same channel.
 
Programming doesn't work that way, you press the programme button twice and it stores the next midi message it receives and exits programme mode. Plus, if that was the case the rocktron would exhibit the same behaviour.
 
The JVM isn't on omni, and I don't have the rocktron plugged in. I only swapped it in for the FX8 temporarily to see if the JVM was functioning.
 
I'm having problems changing the channel on my JVM using the FX8's midi. Sometimes the channel will change, sometime it doesn't and I need to select the same preset several times before the amp responds. Any suggestions? I've double checked the amp using a different midi controller and it works fine, so the FX8 is the problem here. If this is just a quirk of the FX8 it'll be a real shame as it is brilliant, but not being able to rely on it to change the amp channel makes it unusable for me.

Same problem with my JVM410H.
I asked Sonicsam a "step by step" tuto.
 
Same problem with my JVM410H.
I asked Sonicsam a "step by step" tuto.

Ok, I posted this to Rock666 but maybe this will help here also :

- check your midi connenction (from out on the FX8 to in on the JVM)
- are they on the same midi channel (default channel 1) ?
You can reset the JVM to listen to channel 1 by doing the following : Switch the amplifier off (Power switch, not Standby).
Press and hold the FOOTSWITCH / MIDI PROGRAM switch.
Switch the amplifier on (Power switch). Release the FOOTSWITCH / MIDI PROGRAM switch, the LED will start to flash.
Send ANY MIDI command using your FX8.
The amplifier will detect which channel came in and configure itself to listen to that MIDI channel only.
- check on the midi page of the i/o setup menu : midi channel 1, Prog change On (I'm not sure this is necessary, but that's how I did it...)
- in stompbox mode go to the cfg page and scroll down to Midi PC and select the desired MIDI PC number (also check your midi channel again on that same page...)

Put your JVM in Midi Program mode and then turn the Value knob to change the PC (say from 0 to 1 as an example) you will transmit that last PC nr to the JVM (midi led flashes rapidly for a few seconds)
- Save your preset !
 
Did you try to check what messages go out from FX8 with i.E. Midi Monitor, so that you can be sure that JVM receives only one PC message?
 
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