UR44 Inputs 3 & 4 very quiet

When I plug a device into 3&4 on my UR44, it’s extremely quiet. Even with the gain maxed it’s super quiet in Cubase… If it’s moved to inputs 1 or 2, it is instantly louder and has decent recording levels. Why is this?

When phono cables are used, inputs 1 and 2 are “instrument” level, these are for quiet signals like electric guitar and bass which require preamplification.

When phono cables are used, inputs 3 and 4, and the inputs in the back are “line” level. These are for signals that are already amplified such as synthesizers/keyboards, DI boxes, guitar and bass with active pickups (not battery-powered), music players…

All 4 front inputs use preamps if you use XLR cables.

Ok. The issue I’m having at this moment is that the Teenage Engineering Pocket Operator I plug into 3 or 4 doesn’t have a high enough recording volume. It’s self powered. Is it just not a high enough signal?

The other question is this: if I had phantom power on for channels 1 & 2 so that my condenser plugged into channel 1 will function, will the condenser be the only devices receiving the 48v signal if the Pocket Operator is plugged into channel 2 with a 1/4 plug? I don’t want to blow up the PO.