Torpedo C.A.B. M+ Speaker Sim : Headphone Out Suffers from Ground Loop

I bought the Torpedo CAB M to be able to play my Palmer Eins tube amp directly into my headphones. Unfortunately, I was disappointed to find that there's a very loud humming noise when I connect the amp to the CAB M.

While the CAB M comes with a built in ground lift button, it only affects the XLR out, and has no effect on the headphone out. Replacing the CAB M's power supply with a more expensive power supply partially improved the situation (the one included feels very cheap), but the humming was still too loud to use the product as intended.

Based on my experience, that makes the CAB M pretty useless if you're planning to use the headphone out, especially if your amp's output level isn't several orders of magnitude higher than the background hum. If you're buying it mostly for the DI box features and the XLR out, then you might still be happy with it (it does sound great), otherwise it's a bit of a gamble. I'll have to return it unfortunately.