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ADB2
Active Direct Box
Owners Manual
ADB2 Active Direct Box
• Uses standard 9 - 48 volt phantom
power for supply
• Ground Lift for "hum" reduction
• Attenuator switch for connection to line
level or speaker level signals
The ADB2 is an active direct box for convert-
ing a high impedance signal such as a direct
out from a bass amplifier, to a low imped
-
ance signal such as a snake input and a
mixer's microphone input. The Ground Lift is
provided to reduce possible ground hum or
buzz.
Rolls Corporation
Salt Lake City, UT
3/01
SPECIFICATIONS
Input Level: -10 to +40 dB unbalanced
Output Level: -10 to +2 dB balanced XLR Male (pin 2 +)
Bandwidth: 1 Hz to 50 kHz
S/N Ratio: 100 dB
Jacks: (2) 1/4" phone, (1) XLR male
Controls: Attenuator switch, Ground Lift switch,
Power: 9 - 48 VDC Phantom Powered
Size: 2" x 3.5" x 5"
WARRANTY
For information on the Rolls One
Year Limited Warranty, and to reg-
ister this product, visit our website
at www.rolls.com
129-Mar-2001
Date:
Rev:
A
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ADB2.SCH
PHANTOM DIRECT BOX
ROLLS CORPORATION
5968 South 350 West
Salt Lake City, UT 84107
Congratulations and thank you for your purchase of the ADB2 Active Direct Box. The
ADB2 is intended for sending unbalanced signals (up to +40 dB) to a mixing console
or other professional input device. The unit has no transformer, so stray field pickup is
nonexistent. The ADB2 is powered by standard microphone phantom power from 9 -
48 VDC and uses discrete low-noise differential drivers to make it very quiet. The unit
has two 1/4" input jacks wired in parallel, a male XLR output jack, a ground lift switch,
and a three-position attenuator switch.
DESCRIPTION
INPUTS: Two 1/4" unbalanced jacks - wired together in parallel. For connection to line
or instrument level signals.
OUTPUT: One male XLR jack for connection to mixing console or other input device
carrying phantom power.
ATTENUATOR SWITCH: Decreases the input signal by the indicated amount. At 0
dB the signal is not attenuated, at the 20 and 40 dB settings, the signal is dropped by
that amount.
GROUND LIFT: Removes the ground connection of the 1/4" and XLR jacks from the
chassis ground.
ACTIVE LED: Indicates the unit is receiving phantom power.
INSTALLATION
In order for the ADB2 to function it must be connected to a microphone phantom
power source with a balanced XLR cord. The input may be anything from a speaker
source such as a music amplifier, VCR or projector, to an instrument such as a guitar
or High-impedance microphone. Care should be taken to overdrive the ADB2 or there
will be a distorted sound from the unit. Use the lowest attenuator setting that gives
distortion free sound. The ground lift switch should be in the position that yields the
lowest noise.