Just got an UNO and it's a fantastic synth. When I use it with batteries though, after the amp release phase is done a very faint note tone holds for quite awhile and then cuts off. It probably is 10 secs or so and is cutting off when the autotune kicks in. It's very noticeable on notes where the filter is open at the release time. It's the note of the last one you played and if you use the filter cutoff you can hear this filter working on it.
I'm not new to analog synth, I know for sure this is not amp EG release time. This only happens with batteries though. When I use it powered by USB on my laptop with headphones that after-note bleed is not there. It even happens when not connected to a computer at all, with just batteries and a set of headphones. I've tried two sets of batteries, both alkaline and fresh rechargeables.
I would just use it with usb power but the thing is I don't want to use it with my laptop. When I use it with my main studio desktop over usb I get ground loop hum like crazy when I plug into my audio interface. When I switch to batteries when attached to my desktop that hum goes away but then I get the OSC bleed. It's pretty annoying. When I just power with a power brick the ground noise and bleed go away. I could just use the midi cable like that BUT I will be having lots of automation flowing to the Uno and I believe the USB connection will step less with Midi CCs. I've looked at 1/8 inch audio isolators but won't those change the sound? Also what happens when I want to use it with my Ipad with batteries? Not having a separate input for power is really getting in my way. I heard someone got a USB "Ycord" and is feeding it separate power that way. Will that work? Thank you for your time.