Balance Box Microphone Amplifier Specification
Banner
Conford Electronics
 Professional Audio and Process Control
Headphone Amplifier Box
Description
Specification
PDF Download
Stereo Headphone Amplifier Box
Description
Specification
PDF Download
Conford Electronics Logo
Frequency Response
+/- 0.25 dB from 2 Hz to 20 kHz
Noise
Less than -125 dBu referred to the input (Note 1)
Distortion
Less than 0.005% from 2 Hz to 20 kHz
Phase Shift
Less than 1 degree from 2 Hz to 5 kHz
Gain
MIC (microphone mode)
20, 30, 40 and 50 dB (+/- 0.5dB) (Note 2)
LINE (line mode)
-10, 0, 10 and 20 dB (+/- 0.5 dB) (Note 2)
Common Mode Rejection
Greater than 110 dB at maximum gain; 80 dB at minimum gain
Input Common Mode Clipping
+10 dBu at any gain setting
Input Impedance
MIC (microphone input)
2 kOhms (for 100 to 600 Ohm microphones)
LINE (line input)
60 kOhms (bridging input)
Input Clipping Level
MIC (microphone input)
-10 dBu
LINE (line input)
+16 dBu
Output Impedance
50 Ohms
Output DC Offset
Less than 50 mVolts at any gain setting
Output Clipping Level
+10 dBu into 600 Ohms
Connectors
Input
XLR 3 pin female or 3 pole A gauge jack combination socket (Note 3)
Output
XLR 3 pin male (Note 3)
Pin Connections
PIN 1 (sleeve) GROUND; PIN 2 (tip) SIGNAL; PIN 3 (ring) RETURN
To unbalance connect PIN 3 to GROUND
PP3 Alkaline Battery Life
50 Hours typical
External DC Connector
2.5 mm centre pin positive (Note 4)
Dimensions
Width 80 mm; Height 45 mm; Depth 135 mm
Weight
300 gm including battery
Balance Box Specification
Notes to specifications
1.
Measurements of dBu are dB with respect to 0.775 volts
2.
A continuously variable potentiometer gain control version is available to special order
3.
Various adaptors are available to convert to alternative connector standards.
See Accessories
4.
The unit may be operated from an external supply between 6 and 12 volts DC
(maximum) at 15 mA quiescent, 50 mA peak. The recommended voltage is 9 volts.
The supply to each unit should be fully floating and regulated
5.
The circuit is DC coupled and no voltage offsets should be present on the input or output
6.
In the line mode, if ground loop problems are experienced, the signal ground can be disconnected at one end
7.
It is recommended that a nominal peak output of 0 dBu is used to avoid clipping
8.
A fitted belt clip is available to special order
Operating Controls
Front Panel
Gain Selection
Four position rotary switch
Microphone/Line Selection
Two position slide switch
Connectors
Audio input and output
Rear Panel
Battery Holder
PP3 externally accessible
Power on/off
Two position slide switch with LED indicator
Connector
External DC supply

««Description««
Conford, Liphook, Hampshire, GU30 7QW, UK
+44 (0)1428 751469
contact@confordelec.co.uk  www.confordelec.co.uk/
RearPanel
Balance Box Front Panel
7 - Balance Box Microphone Amplifier Description