First thing I did was to upgrade the firmware to 1.12
I think the noise level is comparable to the DP900. It's not loud but it's also not silent as it could be, especially when the outputs are turned off. It's that steady fan noise I can hear 5 meter away from the unit.
Sometimes I would leave my other PSUs running when I google/review something but not with this one. It will remind you that it's running and I turn it off and back on 20 minutes later when I need it.
Comparison DP900:
- 24W at idle
- 30V 61W output, 130W from wall = 58%
- 24V 40W output, 92W from wall = 59%
- 12V 10W output, 48W from wall = 42%
Here are my UDP3305S-E numbers:
- 16W at idle
- 30V 60W output, 128W from wall = 54%
- 24V 40W output, 92W from wall = 53%
- 12V 10W output, 48W from wall = 31%
Did more testing and it seems like higher current has a big impact on efficiency. It looks like the best efficiency is before it has to switch to the next transformer tap - which kind of makes sense due to the higher load on the tap.
10W - 22.4W output results all in the same 72W from the wall. 2A current from 5V to 11.2V - right before the switching point.