MP73

Measurements

Typical values measured with an HP8903A Audio Analyser and a Fluke 187 multimeter. Configuration : Board supply ±27V, Audio circuits supply +24V
Measure	Conditions	Value
Iddle supply current	No input signal	V+ : +105mA V- : -30mA
Input impedance	Gain switch=Low "Level in" pot="7" f=1kHz	1.2kΩ
Maximum input level	f=1kHz	limited by input TX : +20dBu@1kHz +17dBu@50Hz +3dBu@20Hz
Maximum output level before clip	f=1kHz	+27dBu
Maximum gain	Gain switch=Low	+41dB
Maximum gain	Gain switch=Mid	+55dB
Maximum gain	Gain switch=High	+70dB
EIN	Zin=150Ω Gain switch=Mid Bandwidth=0-30kHz	-124dBu
EIN	Zin=0Ω Gain switch=Mid Bandwidth=0-30kHz	-124dBu
Frequency response at Low gain	Overall gain=+20dB Gain switch=Low Lvl in="4.5", Lvl out="10" Zin=150Ω Deviation=-1dB	10Hz-40kHz
Frequency response at mid gain	Overall gain=+40dB Gain switch=Mid Lvl in="7", Lvl out="10" Zin=150Ω Deviation=-1dB	10Hz-40kHz
Frequency response at high gain	Overall gain=+60dB Gain switch=Hi Lvl in="8", Lvl out="10" Zin=150Ω Deviation=-1dB	10Hz-30kHz
THD	f=1kHz Gain=+42dB Vout=+16dBu	< 0.0035%
CMRR	f=100Hz Gain switch = Mid	-109dB
CMRR	f=10kHz Gain switch = Mid	-74dB

Signal injected into input XLR, scope on output XLR, going through both transformers.


Small amplitude square wave output f = 1kHz gain = minimum (+41dB) scale = 0.2V/div	Large amplitude square wave output f = 1kHz gain = +41dB scale = 5V/div	Large amplitude square wave output f = 10kHz gain = +41dB scale = 5V/div