Hermod Noise when sending Midi or CV to an External Instrument


Im getting a hiss from the Hermod when sending anything to an external instrument, not within my case. For this particular example, I tried sending midi to my 0-Coast and sending it CV and Gate I get that hiss. The 0-Coast is noise free if I send it midi from my keystep.

Any thoughts or remedies? Thanks!!

It is in a Make Noise Case with the power it came with. Heres a photo of the rack.

its likely a ground loop… :frowning:

Im guessing you’re going keystep (midi din) -> hermod (cv/gate)-> o-coast?

do you get noise if you unplug the keystep, and sequence from hermod?

if you search for resources on ground loops you’ll find recommendations,
eg. make sure you plug everything into same plug socket - its one of those things I usually eliminate by trying different options (e.g. sometimes I power via a usb battery bank)
… i think the ‘ultimate’ solution is a DI box, but Ive not had to resort to that…

I suspect you’ll find something on the arturia faq and possibly o-coast, as its not an uncommon issue unfortunately :frowning:

Keystep to Hermod USB Host. Midi or CV out to 0-Coast.

I’ve already tried plugging everything in to the same plug socket and yes, I get noise when the Keystep is unplugged as well. Even when theres no power on the 0-Coast If I put voltage into it and its plugged into the mixer theres an instant hiss… Would love to figure this out asap… :frowning:

I’ve not got a keystep but remember seeing posts complaining it was introducing noise - and there was talk of using a usb isolator (?) - I think something that separates the power supply from the usb data.
But as I say I don’t have one, so this is secondhand knowledge :wink: but might point you in a direction?

What I would try is powering it from a usb battery pack and then using midi din - just to try to remove the usb host power from the equation.

The noise is present without the keystep as well… :frowning:

ok, so sounds like the issue is on the o-coast, or both :frowning:

I know, its really frustrating when this happens, but as i said at the top, unfortunately its not that uncommon, and usually not the ‘fault’ of one piece of gear - it seems to happen to me most when I’m connecting something that use a ‘wall wart’ (also computer connections tend to do it) and of course at the most inopportune time!

perhaps the following video will give you some ideas on what to try

I’ve been meaning to get a DI/isolator, as that appears to be the ‘sure fire’ way to resolve, but as i don’t have one I usually end up messing about using usb battery banks… as i have plenty of those (and the relevant voltage converters)

Hello guys,

We found a software fix that will be in the next hermodOS version, soon to be released, improving a lot the noise amount!

To provide full transparency, we never experienced by ourself this problem with Hermod (unless with a cheap power supply) and according to users, it seems quite rare. But thanks to some users of this forum we were able to find and fix the issue.

We know that ground problems can be really tricky to troubleshoot. I take advantage of this message to list here some advices, helping you to reduce the noise of a module:

  • try to change the module position in your eurorack case
  • do not screw the module to see if it reduces the noise, or maybe use plastic screws
  • try an other 15V power supply adapter
  • try an other case (or an other 12V/-12V/5V power board)
  • try an other power outlet in your studio, without using outlet power strip
  • use a linear power supply (the best way to get rid of noises)
  • if the problem appears only when you use the USB HOST, use a special Y usb cable that power your usb device with a separated supply

Have a nice day, and stay safe!

1 Like