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Interference from trigger output board

RevokRevok
edited March 2015 in General
Hi

I've once again been delving deep into the LXR these past weeks. It never ceases to surprise me!

One issue I've noticed in the past (and once posted about) was a very high pitched whine coming from the outputs sometimes, although I couldn't quite pinpoint when and how it occurred.

Yesterday I discovered the whine is present only when one of the trigger outputs is connected to something else. I've tried different power outlets for the LXR and the triggered slaves and I've tried several types of cables to trigger with to no avail. It occurs with any machine I trigger. So by elimination the LXR itself is the culprit. 

Is there anything I can technically do to solve this? Some kind of shielding between the extension and the main board perhaps? A ground on the trigger extension?

I'm definitely not squeamish about a bit of hiss here or there, but this is a particularly irritating noise that gets on the nerves.

Thanks for helping out.

Rvk



Comments

  • jbdiverjbdiver
    There is some discussion of this issue in this thread:


    Basically a ground loop is forming when you connect the LXR+triggers to another synth like a eurorack modular.  The intensity of the noise may vary based on your particular setup. I was able to eliminate it by connecting a ground loop isolator between the trigger output and my modular input. The problem with this solution is that it would require several ground loop isolators and a bunch of cable adapters. You end up with a mess of cables with bulky isolators attached to them. You could attach a ground loop isolator on the lxr audio outputs, but unless it's a really high quality isolator it will significantly impact low frequencies -- not a good solution for a drum synth in my opinion. My guess is that the trigger board would need to be redesigned to provide better signal isolation to resolve this problem.
  • RevokRevok
    *Sorry I missed that thread, feel free to merge mine into it!*

    By ground isolators I assume you mean DI boxes?
    Far from practical indeed. I was really hoping for a simple hack.

    I'm not versed in electronics but isn't there some component or simple circuit that can divert incoming current from the outgoing connections? The incoming clock/reset i never use anyway.

    Rvk


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