Legend Audio ISA 828 Stereo Amplifier User Manual


 
Specifications
Mic Input Response
Gain range = 0dB to 60dB in 10dB steps
Input Impedance, variable as follows:-
Switched Impedance setting Equivalent Input Impedance at 1kHz
Low 600
ISA 110 1400
Med (Medium) 2400
High 6800
EIN (equivalent input noise) = -126dB measured at 60dB of gain with 150 Ohm terminating impedance and
22Hz/22kHz bandpass filter
Noise at main output with gain at unity (0dB) = -97dBu measured with a 22Hz/22kHz bandpass filter
Signal to noise ratio relative to max headroom (9dBu) = 106dB
THD at medium gain (30dB) = 0.0008% measured with a 1kHz -20dBu input signal and with a 22Hz/22kHz bandpass filter
Frequency response at minimum gain (0dB) = -0.5dB down at 10Hz and –3dB down at 110kHz
Frequency response at maximum gain (60dB) = –3dB down at 16Hz and –3dB down 85kHz
CMRR=91.8dB (Channel 1, 1kHz, maxiumum gain)
Crosstalk Channel to Channel: with 10dB@1kHz input to chA, chB output =102dBrA. With 10dB@10kHz input to chA,
chB output = 84dBrA
Line Input Response
Gain range = -20dB to +10dB in 10dB steps
Input Impedance = 10kΩ from 10Hz to 200kHz
Noise at main output with gain at unity (0dB) = -96dBu measured with a 22Hz/22kHz bandpass filter
Signal to noise ratio relative to max headroom (24dBu)=120dB
Signal to noise ratio relative to 0dBFS (+22dBu) = 118dB
THD at unity gain (0dB) = 0.001% measured with a 0dBu input signal and with a 22Hz/22kHz bandpass filter
Frequency Response at unity gain (0dB) = 0.3dB down at 10Hz and –3dB down at 122kHz
Instrument Input Response
Gain range = 10dB to 40dB continuously variable
• Input Impedance:
High >1MΩ
Low > 300kΩ
Noise at minimum gain (+10dB) = -90dBu measured with a 22Hz/22kHz bandpass filter
Noise at maximum gain (+40dB) = -62dBu measured with a 22Hz/22kHz bandpass filter
THD at minimum gain (+10dB) = 0.002% measured with a 10dBu input signal and with a 22Hz/22kHz bandpass filter
Frequency Response at 10dB gain with -10dB input = 10Hz-200kHz +/- 0.6dB
Frequency Response at 40dB gain with -40dB input = -2.5dB down at 10Hz and 0dB at 200kHz
High Pass Filter
Roll off = 18dB per octave 3 pole filter
Fixed Frequency 75Hz measured at the 3dB down point
Input Meter
Calibrated in the detent position for 0dBFS = +22dBu and indicates the level after the High Pass Filter and before the
Insert Send output. LED levels are as follows:
0 = +22dBu
-2 = +20dBu
-6 = +16dBu
-12 = +10dBu
-18 = +4dBu
-42 = -20dBu
Calibration is adjustable to allow 0dBFS to equal +10dBu to +26dBu
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