The headphone output on my ModDwarf that just arrived today is very noisy too. Using the power supply that came with it out of the box. It has the same noise regardless of whether I plug in any other connectors (other than power and headphones).
I also have had a similar but quieter noise on my ModDuo, though I am using a different power supply for that. Swapping the powersupplies results my ModDuo output become more noisy than it was before, and the ModDwarf being less noisy than it was before. But the ModDwarf is still much noisier with the good power supply than the ModDuo is with the bad power supply that came with the ModDwarf, so most of the problem seems to be with the internal circuitry of the ModDwarf. (note: I’m plugging both power supplies into the same wall outlet.) So in summary the noisiness from most noisy to least noisy is:
- ModDwarf with its original power supply
- ModDwarf with my own powersupply (from a labtop)
- ModDuo with the ModDwarf’s original power supply
- ModDuo with my own powersupply (from a labtop)
Now a trick as mentioned is to insert an audio ground noise loop isolator between the headphone output and your headphones…I happened to have one (I got mine for $6 from PJRC Store). That dramatically cuts down on noise coming into the headphones.
Though at least there is no noise on the actual balanced line outputs, when routed to another mixer or interface which accepts balanced line as input.
Anyway, as I guess I am a betatester for moddwarf, I’d recommend the devs take a look at this ground noise problem…and maybe consider including a headphone ground loop isolator when shipping.