pitchblender

Nice one, thanks @reza for clearing that up, much appreciated! The penny's dropped, and I can sleep easy, knowing that I can now turn the Deluge into a sonic VGER (from the 80s Star Trek movie ) and all my existing half-baked lame learning projects are safe

A future suggestion to avoid the USB adapter sticking out like a wobbly 'please knock me and lose your data or short the Deluge or damage the thing' afterthought - buy a short right-angle USB male A to female A extension cable (plus the mentioned adapter) so everything is compact and secure at the back of the Deluge. I'm using a common right angled male USB A to male USB B for charging and as a bonus it also protects the on/off switch from accidentally being switched off!
Can't find a cable though with the required ends on it yet, if one exists at all...
I'm probably going to velcro the adapter to the side of the Deluge (if I can find a cable short enough) or even splice a cable together from old broken ones once I know what the score is with v3.x.
You could also get the more common USB A male to B male cable and use a female to female USB B adapter on the B end of that...
All theoretical so far, but I want to fit my D into a Peli case with minimal extraneous dongle hassle...

Ditto +1

I recently tried using powered USB hub with Deluge connected to MyVolts 9V 1A centre-negative USB cable/adapter and I had problems with USB MIDI, even using a powered USB hub. I switched to an old 12V 3A centre-positive AC/DC PSU with polarity-switching cable adapter and it works fine. Maybe a current-draw issue?

But then I also ended up getting the tiny Retrokits RK-006 USB/TRS MIDI hub and if you plug the Deluge USB into a USB hub (I used a standard shielded right-angled USB-B plug to USB-A plug cable) attached to the RK-006 instead, USB MIDI works a treat. I tried a 10x socket powered USB hub and every device attached to the hub was sending/receiving USB MIDI just fine, and the Deluge did not need extra power into the barrel DC socket, but was still charging off the USB hub. One less cable/PSU to worry about.
The same RK-006 also leaves me with another 2x MIDI TRS INs and 10x MIDI TRS OUTs, so it's a powerful little device for the money. Even has latency compensation for each MIDI device, but you do need to plug it in to computer or phone to access settings.
Pity it's not built in to the Deluge!