Cable Shielding Question

Poparad

Poparad

Power User
I have a Vafam front panel routing the rear connections to the front for easier access in my rack. A problem I've encountered is that my MIDI cables run close to my ouput audio cables, and the pulse of the tap tempo data is often audible in the output, due to interference in the cables. Is there a way I can isolate/shield either the MIDI or audio cable to prevent crosstalk?

Interestingly, when I have my smaller, non-MFC floorboard connected to the MIDI jacks, I don't get any crosstalk. When I have the MIDI jacks unpluged at the front panel (but still connected to the Axe in the rear), I often get crosstalk. So far I've resorted to disconnecting the MIDI cables when not using the small floorboard, but it's a hassle to open up the rear of the case and constantly plug and unplug cables (sort of defeating the entire purpose of a front panel).
 
Some ideas,

Cable routing, rather avoid running cables close and parallel
Shielding can help unless you shield and earth at both cable ends
Audio cables normally ARE shielded, check if shield is connected on both cable ends
Try ground lift on Axe Fx II rear panel ("normally closed")
Check thorougly the quality of wire soldering of your signal cables, a bad soldering can be at the origine of hum
and so on and on..
 
lauke-lux said:
Some ideas,

Cable routing, rather avoid running cables close and parallel
Shielding can help unless you shield and earth at both cable ends
Audio cables normally ARE shielded, check if shield is connected on both cable ends
Try ground lift on Axe Fx II rear panel ("normally closed")
Check thorougly the quality of wire soldering of your signal cables, a bad soldering can be at the origine of hum
and so on and on..
Click to expand...

It's not a hum that's the issue; it's a clicking sound (like the metronome) that's perfectly in time with the tempo light on the front panel of the Axe. It's the burst of data going through the MIDI cable to sync a floor board with the Axe for tap tempo functions.
 
Poparad said:
It's not a hum that's the issue; it's a clicking sound (like the metronome) that's perfectly in time with the tempo light on the front panel of the Axe. It's the burst of data going through the MIDI cable to sync a floor board with the Axe for tap tempo functions.
Click to expand...

Both are magnetic coupling issues. Shielding your midi-cable and securing it's well connected to mass each side, coulde help.
 
You can set SEND REALTIME SYSEX to NONE in the I/O menu MIDI page to disable sending the clock when desired. Note this will also disable the tuner display on the MFC.

Standard MIDI and instrument cables are already shielded, though higher quality ones will be shielded better. Your best bet is to keep the MIDI and Audio cables as far away from each other as possible and avoid running them parallel to each other, especially audio input cables. Don't bundle all the cables together. It looks neat, but you are asking for noise and crosstalk. IF possible, move the MIDI and audio connectors to opposite sides of your connection panel and route the cables on opposite sides of the rack. Axe already has MIDI on one side and audio on the other side of the back panel.
 
Last edited:
mr_fender said:
You can set SEND REALTIME SYSEX to NONE in the I/O menu MIDI page to disable sending the clock when desired. Note this will also disable the tuner display on the MFC.

Standard MIDI and instrument cables are already shielded, though higher quality ones will be shielded better. Your best bet is to keep the MIDI and Audio cables as far away from each other as possible and avoid running them parallel to each other, especially audio input cables. Don't bundle all the cables together. It looks neat, but you are asking for noise and crosstalk. IF possible, move the MIDI and audio connectors to opposite sides of your connection panel and route the cables on opposite sides of the rack. Axe already has MIDI on one side and audio on the other side of the back panel.
Click to expand...

I run my MFC via ethercon, so if I disabled the Sysex to stop the interference, I'd lose major functionality. I guess the problem for me is that I added the MIDI jacks later to two open spots on my front panel, which happen to be near my audio outs.
 
Not to be a smart ass, but move jacks and place more space between them. I've got a panel as well and I get no noise... 1.Powercon 2.Tuner 3.Ethercon 4.Midi out 5.Midi In 6.USB 7.XLR L 8.XLR R 9. 1/4 L 10. 1/4 R 11. Input jack that works in tandem wth the feed through in last position. 12.Feed through. Slammed tight with stuff and not a peep.
 
MGW said:
Not to be a smart ass, but move jacks and place more space between them. I've got a panel as well and I get no noise... 1.Powercon 2.Tuner 3.Ethercon 4.Midi out 5.Midi In 6.USB 7.XLR L 8.XLR R 9. 1/4 L 10. 1/4 R 11. Input jack that works in tandem wth the feed through in last position. 12.Feed through. Slammed tight with stuff and not a peep.
Click to expand...

I'm probably going to have to reorder the panel. It's kind of a last-resort option, as it's very labor intensive and it came with labels installed for the current locations, and I'm not sure I could move them without ruining them all.
 
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