Active Direct Box Model 1
The Rice Audio® Active Direct Box Model 1 (ADB1) is a versatile high to low impedance adapter with a variable gain amplifier. It is designed for general purpose stage use as an upgrade replacement for common passive direct boxes. It works well with most pickup outputs. The ADB1 uses two three conductor 1/4 inch phone input jacks to accept either balanced or unbalanced signals and it has a male XLR type output jack compatible with standard microphone cables. Normally one input jack is used as a thru output for another on stage amplifier or other device. Several devices can be daisy chained in this way;
An amplifier has several advantages over a transformer adapter: the stronger signal power will overcome frictional noise and electromagnetic interference from the microphone cable, the amplifier provides a one-way buffer that will prevent reflected signal from resonating back to a microphone or pickup, it provides a good output impedance match regardless of the input impedance, it also provides a level adjustment on stage;
Feature List:
- Enclosure is a lightweight die-cast aluminum alloy enclosure strong enough to survive being stepped on. Compact size ( 4.75" x 2.5" x 1.5" ) fits easily into pocket or instrument case. Durable gloss black powder coat finish, Stackable with rubber feet;
- Spring loaded gain knob and switch caps retract if stepped on;
- Flexible power requirements: Normally operates on remote phantom power only but can also operate from an external battery pack or an AC adapter (sold separately), Dual power input jacks enable several units to be powered from a single power supply, i.e., daisy chained, An LED indicates when power is present;
- Switchable ground lift circuit rejects AC hum is problem situations;
- Phase invert switch is helpful when multiple microphones or pickups are used on the same sound source;
- Ultra quiet and accurate wide range LM833 bi-polar audio amplifier;
- Dual common high impedance (47K) 1/4” input jacks can accept either balanced or unbalanced signal inputs and are protected from phantom power; Using an A3F to three conductor phone adapter cable the ADB1 can be used to amplify a low impedance source such as a dynamic microphone while adding a local gain adjustment;
- Wide range gain adjustment from -10dB to +10dB. Attenuation is sometimes needed for high level input signals. At the -10dB setting the attenuation level is similar to that of a transformer adapter;
- Available in several other colors and/or with custom printed labels.