Sonifex RB-MA1

The Sonifex RB-MA1 consists of a low noise microphone pre-amplifier for converting mic level signals to line level, or for driving long lines from microphones to mixing equipment. The connections and controls are on the rear panel. The microphone input is an XLR-3 type and is electronically balanced. The gain for the input can be adjusted by a recessed pre-set potentiometer, which allows for the use of both dynamic and powered microphones. The line output is of an XLR-3 type and is electronically balanced. It can be wired unbalanced by grounding the non-phase signal, allowing you to feed both balanced and unbalanced equipment. There is a switch to control a high pass filter (low frequency roll-off at 125Hz) and to provide phantom power at +48V to the connected microphone.

RB-MA1 Block Diagram.

Technical Specification For RB-MA1
Audio Specification
Maximum Input Level:	-10dBu
Maximum Output Level:	+28dBu
Low Frequency Roll-Off:	125Hz @ 6dB/octave
E.I.N.:	130dB
Common Mode Rejection:	>60dB typically
Frequency Response:	20Hz to 20kHz ±0.1dB (600 Ω load, ref 1kHz)
Input Impedance:	2 kΩ nominal balanced
Output Impedance:	<50 Ω
Gain Range:	Adjustable 36dB to 75dB gain
Distortion:	0.01% THD @ 1kHz, ref +8dBu output
Phantom Power:	48V
Connections
Input:	1 x XLR 3 pin female (Balanced)
Output:	1 x XLR 3 pin male (Balanced, can be unbalanced)
Mains Input:	Filtered IEC, switchable 110-120V, or 220-240V, fused, 6W max
Fuse Rating:	Anti-surge fuse 100mA 20 × 5 mm (230VAC) Anti-surge fuse 250mA 20 × 5 mm (115VAC)
Equipment Type
RB-MA1:	Single microphone amplifier
Physical Specification
Dimensions (Raw):	28 cm (W) x 10.8 cm (D) x 4.2 cm (H) (1U) 11” (W) x 4.3” (D) x 1.7” (H) (1U)
Dimensions (Boxed):	36 cm (W) x 20.5 cm (D) x 6 cm (H) 14.2” (W) x 8” (D) x 2.4” (H)
Weight:	Nett: 0.90 kg Gross: 1.35 kg Nett: 2lbs     Gross: 3lbs