AR-133 Active Direct Box

Why do I need a DI Box?
Signals from electronic instruments such as guitars, keyboards and similar sound sources generally have a low level, high impedance output, which will not interface with the low impedance balanced input found on professional sound mixing consoles. Furthermore these signals cannot be driven up long cable lengths without serious loss of level and degradation.

The DI box converts this signal to a more suitable form without interfering with or modifying the signal at the instrument source, and should provide freedom from ground and power line related problems.

Passive DI boxes have limited applications as they will inevitably affect the signal source for guitar type applications, and can also have an insertion loss of around 20 dB.
The only safe and predictable way to provide direct feeds from instruments or other sources is by using an Active DI box utilizing an input amplifier driving an output transformer.
The AR-133 fulfills all the requirements of an active DI and more.

KEY FEATURES:
• Switchable input attenuation 0 dB for guitar-type pickups -20 dB for line level signals -40 dB for speaker feeds
• Matches the level and impedance with unity gain without loading the source
• Can drive signals up long cable lengths
• Powered from console phantom power or internal battery
• Automatic switchover to battery if phantom power fails
• Parallel Link Jack output to feed amplifiers directly
• Parallel XLR input for converting unbalanced outputs to balanced lines

The audio signal path of the AR-133 is an enhanced design based upon the long established BSS AR-116, now regarded by many as a reference unit.

The sound quality, particularly on acoustic guitar and bass guitar pickups, is recognized as outstanding.

The uses, however, are not limited to guitars or keyboards. The AR-133 is suitable for use whenever it is critical to match levels and impedances, sources need isolation or long cables are used.

The provision of both jack and XLR connectors on the input further extends the use of the AR-133 with a multitude of source devices.

Powered from the console or battery
The AR-133 takes its power either from the standard microphone phantom powering available from the desk, or from an internal 9V battery. When phantom is used, the power led on the AR-133 is lit continuously. If the phantom fails, the battery immediately takes over, with a flashing led showing battery use.

Earth lift for solving grounding problems
The earth lift switch enables the input signal’s earth to be separated from the output ground, a quick and easy way to prevent ground-loop problems.

Typical Applications Guitar pickup feed
Suggested Attenuation Setting 0 dB
The low level, high impedance signal from the guitar pickup is translated by the AR-133 into the high-level, low impedance balanced signal required by the front-of-house console.

Keyboards - line level feed
Suggested Attenuation Setting -20 dB (line level) or -40 dB (amp level)
The line level output of the keyboard is balanced and matched by the AR-133.
In multiple keyboard setups where a mixer-amp is used for monitors, the AR-133 can be used to save on DI boxes by taking the output of the amplifier as the interface to the console, rather than using separate DI’s for each keyboard. In this case, either a line output or the speaker output can be used, depending on the mixer/amp.

Speaker feed
Suggested Attenuation Setting -40 dB
Taking a feed from the amplifier output allows the post-amplifier, post EQ/effects signal to be fed to the console, meaning that a particular effect/amp sound can be sent to the mix.