The U-380's front panel has three small raised buttons situated above its large volume control knob. The first adjusts mute, gain, cartridge loading and balance settings; the second is for power on/standby; and the third selects the source. To the left of the knob are gain settings—gain is adjustable in 18 steps, which are illumined but impossible to read from a distance—and to the right, source options. Small white LEDs—a novelty in the age of red, green, and blue—indicate setting choices. Most functions, including volume, input, cartridge loading, and mute, are also adjustable via a small Apple remote.
The U-380's mixed-mode DAC, which Børresen describes as "the closest thing you can get to a R2R ladder DAC," uses a 24/192 Texas Instrument Burr-Brown 1794. "When you turn down the volume, the specifications get better and the noise doesn't increase. This is because we increase the amplifier's feedback ratio around the line stage, which lowers noise and distortion and heightens performance. Technically, we do this by using a low-noise precision DAC to set the resistor values in the feedback network."
The U-380's phono section has 62dB gain that, according to the product manual, is "suitable for most low to medium output MC cartridges." Cartridge load impedance is adjustable in 18 steps from 50 ohm to 10k ohm. The manual includes a cartridge balance setting chart.