ART USB DI

Product overview

The ART USB DI is a USB direct box that gets audio from a computer to a mixer or PA system, with high quality digital to analogue conversion and balanced, transformer isolated XLR outputs.

Custom output transformers isolate the digital and analogue elements, eliminating ground loops and system noise and providing a pristine signal to any analogue sound system. A front panel switch selects between a fixed volume at the main outputs or variable adjustment with the large Level knob, which also controls the 1/8 inch headphone output. A ground lift switch on the rear panel engages an extra layer of hum protection. The USB DI is class compliant and bus powered, so it does not require driver software or an external power supply, and it comes in a compact, rugged, stackable all aluminium chassis.

Key features

• USB 2.0 connection (Type B), also compatible with USB 1.1
• Supports 32 kHz, 44.1 kHz and 48 kHz sample rates
• Transformer isolated XLR outputs, left and right
• Fixed or variable main output level
• Level control adjusts monitor or main + monitor volume
• Switchable ground lift on the rear panel
• Class compliant: no driver software required
• Bus powered: no external power supply required

Fixed or variable main outputs

With the Main Outputs switch pressed (Fixed, lit blue) the XLR outputs stay at a fixed level of 650 mV RMS (-1.5 dBu) and the Level knob adjusts only the headphones, so the level is set at the preamp or mixer the USB DI feeds. With the switch released (Variable, lit red) the Level knob controls the left and right outputs and the headphones together. The lit switch also shows that the unit is powered over USB.

Isolation against hum and buzz

Computers, projectors and many other consumer devices can induce hum and buzz in audio paths through stray voltages and ground loops. The isolation transformers on the main outputs remove them, and the rear Output Ground switch (Grounded / Float) lifts pin 1 on the XLR jacks for another layer of hum protection.

Plug in and play

The computer sees the USB DI as a standard "USB Audio DAC", powers it over the USB bus and controls the sample rate. The standard driver is built into most modern operating systems, and the unit is normally selected automatically as the default audio device; the same setting may also be made in the recording software.

Headphone monitoring

The 1/8 inch stereo TRS monitor output delivers up to 150 mW per channel at 16 Ω and accommodates a wide variety of headphones. In the Fixed mode it lets you monitor and change the headphone level without changing the level at the main outputs.

In the box

• USB DI USB direct box

ART USB DI: frequently asked questions

Does the USB DI need driver software or a power supply?

No. It is class compliant and bus powered over USB (500 mA max.).

Which sample rates does it support?

32 kHz, 44.1 kHz and 48 kHz; the computer controls the sample rate.

What do the Fixed and Variable modes do?

Fixed keeps the XLR outputs at a fixed level (-1.5 dBu max.) while the Level knob sets the headphones; Variable lets the Level knob set the XLR outputs and the headphones.

How does it deal with hum?

Custom output transformers isolate the digital and analogue sides, and a rear ground lift switch lifts pin 1 on the XLR outputs.

Where can I buy the ART USB DI in India?

The ART USB DI is available from Shivansh Electronics, Kolkata, West Bengal, India, with delivery across India.

Workflow 1: Laptop playback into a PA system

Presenters, events and venues playing audio from a computer.

Connections

Setup

1. Connect the USB DI to a USB port of the computer: it powers up and the switch lights.
2. Select "USB Audio DAC" as the playback device if the computer does not do it automatically.
3. Choose Fixed or Variable output and set the level.

Tip: Connect directly to a USB port of the computer rather than through a shared hub.

Workflow 2: Fixed level feed to a mixer

Engineers who set the gain at the mixer.

Connections

Setup

1. Press the Main Outputs switch (Fixed, lit blue).
2. Set the gain at the mixer channel.
3. Use the Level knob only for the headphones.

Tip: In the Fixed mode the outputs stay at -1.5 dBu max. (650 mV RMS).

Workflow 3: Desk volume control for powered speakers

Small rooms and installations with powered speakers.

Connections

Setup

1. Release the Main Outputs switch (Variable, lit red).
2. Use the Level knob to set the speaker volume.

Tip: ART suggests Variable mode with the Level control fully anticlockwise before powering up a connected system.

Workflow 4: Removing hum from a computer

Any system where a computer adds hum or buzz.

Connections

Setup

1. Rely on the transformer isolated outputs.
2. If hum remains, set the rear Output Ground switch to Float to lift pin 1.

Tip: Computers, projectors and other consumer devices can induce noise in audio paths.

Workflow 5: Headphone check before going live

Operators cueing audio from a computer.

Connections

Setup

1. Plug headphones into the monitor output.
2. In the Fixed mode, adjust the headphone level without changing the main outputs.

Tip: The headphone output delivers up to 150 mW per channel at 16 Ω.

Workflow 6: Projector or media player audio into a receiver

Classrooms, meeting rooms and AV installations.

Connections

Setup

1. Connect the USB audio source to the USB DI.
2. Connect the XLR outputs to the line inputs of the receiver or mixer.

Tip: ART names computers, projectors and other USB audio sources as typical sources.