Specifications, Mic inputs, Line inputs – Focusrite ISA428 MkII Rackmount 4-Channel Microphone Preamp User Manual
Page 15: Instrument inputs, High pass filter, Meters
15
Specifications
Mic inputs
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Frequency response at minimum gain (0dB): -0.35dB at 20Hz and –3dB at 122kHz.
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Frequency response at maximum gain (60dB): –2.5dB at 20Hz and –3dB 103kHz.
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Gain range: 0dB to +60dB in 10dB steps, plus 0dB to +20dB continuously variable trim.
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Maximum headroom: +7.4dBu.
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THD+N: 0.0009% (measured at 1kHz -20dBu input signal, at 30dB gain setting, with a 20Hz/22kHz bandpass filter).
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Noise EIN: -126dB (measured at 60dB of gain with 150Ω termination and 20Hz/22kHz bandpass filter).
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Noise at main output with unity gain: -98dBu (measured with a 20Hz/22kHz bandpass filter).
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SNR: 123dB (relative to max output 25dBu).
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SNR: 120dB (relative to 0dBFS (+22dBu).
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CMRR: 88dB.
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Input impedance, variable as follows:
Switched impedance setting
Equivalent input impedance at 1kHz
Low
600Ω
ISA110
1400Ω
Med (Medium)
2400Ω
High
6800Ω
Line inputs
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Frequency response at unity gain (0dB): -0.3dB at 20Hz and –3dB at 94kHz.
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Gain range: -20dB to +10dB in 10dB steps, plus 0dB to +20dB continuously variable trim.
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Maximum headroom: +25.4dBu.
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THD+N: 0.002% (measured with +4dBu input signal, 0dB gain setting, with a 20Hz/22kHz bandpass filter).
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Noise at main output with unity gain: -91dBu (measured with a 20Hz/22kHz bandpass filter).
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SNR: 116dB (relative to max output 25dBu).
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SNR: 113dB (relative to 0dBFS +22dBu).
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Input Impedance: 10kΩ.
Instrument inputs
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Frequency response at +10dB gain: -0.2dB at 20Hz and 0dB at 200kHz.
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Frequency response at +40dB gain: -3dB at 20Hz and –3dB at 38.4kHz.
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Gain range: +10dB to +40dB continuously variable.
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Maximum headroom: +11.5dBu.
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THD+N: 0.006% (measured with –20dBu input signal, at minimum gain (+10dB), with a 20Hz/22kHz bandpass filter).
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Noise at main output with minimum gain (+10dB): -95dBu (measured with a 20Hz/22kHz bandpass filter).
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Input Impedance
>
1MΩ.
High pass filter
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Roll off = 18dB per octave 3 pole filter.
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Frequency range: 16Hz to 420Hz (continuously variable, measured at the 3dB down point).
Meters
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6 LED meter is calibrated 0dBFS = +22dBu (the maximum level which can be correctly converted by the optional internal
A/D converter before overload occurs). The meter calibration points are as follows:
Meter panel calibration value in dBFS
Equivalent dBu value
0dBFS
+22dBu
-2dBFS
+20dBu
-6dBFS
+16dBu
-12dBFS
+10dBu
-18dBFS
+4dBu
-42dBFS
-20dBu