VLT2 Noise buzzing Problem when used with MIDI input

  1. #1 by Sandrine Sims on 03-26-2018
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    Posts: 10

    VLT2 Noise buzzing Problem when used with MIDI input

    I have noticed a rather annoying problem when using MIDI input on the VLT2
    I first connected a BeatStep Pro (known to be noisy) via MIDI to the MIDI input on the VLT2. As soon as I did, I heard a rather loud buzzing from the mixer.
    At first I blamed the BeatStep Pro, but then I patched the MIDI over to a Roland piano and a different type of hum emerged.

    Granted, I am presently connecting the VLT2 into the mixer via 2 mic lines (as I'm out of line level inputs) so it's probably more sensitive, but I had to investigate further.

    It turns out the VLT2 MIDI input is not isolated. I disconnected the ground line on the MIDI patch and boom the noise is gone. If anyone else experiences this, that's the way to fix it.

    I'm not sure if the jack case makes a ground connection in the VLT2 also (some MIDI cords connect pin 2 center pin to the "chassis" of of plug) but I'm using TRS plugs so that's not a concern.

    I find it rather odd that the MIDI input (isolated with an opto coupler) still has a ground pin attached.