Specifications
Two channel classic Focusrite ISA transformer-based preamps
Front panel, per channel:
- 1/4″ instrument input
- Variable input impedance – Low, ISA 110, Medium, High
- Input selection – Mic, Line, Instrument
- 0 – 30 dB/30 – 60 dB gain switch
- Phantom power switch
- Phase invert switch
- 0 – 60 dB gain in 10 dB steps
- 0 – +20 dB continuously variable trim
- Variable high-pass filter with on/off switch
- Insert point on/off switch
- Eight-LED user-calibrated level meters
- Single power switch
Rear panel, per channel:
- XLR-F mic inputs
- 1/4″ TRS line inputs
- 1/4″ TRS Sends
- 1/4″ TRS Returns
- XLR-M line output
- Single peak meter calibration dial
- Single IEC power socket
Measured Performance
Maximum Input and Output Levels |
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Maximum Output Level | +24 dBu with a THD+N < 0.01% at 1kHz measured with 150 Ω source impedance and 22Hz/22kHz band-pass filter | |
Maximum Microphone Transformer Input Level | +7 dBu with a THD+N < 0.7% at 1kHz measured at 0 dB of gain with 150 Ω source impedance and 22Hz/22kHz band-pass filter | |
Mic Input Response |
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Gain range | 0 dB to +60 dB in 10 dB steps, plus 0 dB to +20 dB continuously variable trim | |
Input Impedance | Switched Impedance setting Equivalent Input Impedance at 1 kHz |
Low = 600 Ω ISA 110 = 1.4 kΩ Med = 2.4 kΩ High = 6.8 kΩ |
EIN (Equivalent Input Noise) |
Measured at 60 dB of gain with 150 Ω source impedance and 22 Hz-22 kHz band pass filter |
-127 dB |
Noise | Noise at output with unity gain (0 dB) and 22 Hz-22 kHz band pass filter | -97 dBu |
Signal-to-Noise Ratio | Measured with 150 Ω source impedance and 22 Hz-22 kHz band pass filter | 121 dB relative to max output +24 dBu |
Total Harmonic Distortion + Noise | Measured with a -20 dBu input signal at +30 dB of gain and with a 22 Hz-22 kHz band pass filter | < 0.0007% at 1 kHz |
Frequency Response | At minimum gain (0 dB) | -0.5 dB at 10 Hz, -1 dB at 135 kHz, relative to 1 kHz |
At +60 dB gain | -6 dB at 10 Hz, -1 dB at 115 kHz, relative to 1 kHz |
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CMRR (Common Mode Rejection Ratio) | -94 dB for mic input at 60 Hz for max. output = +24 dBu -91 dB for mic input at 10 kHz for max. output = +24 dBu |
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Crosstalk Channel to Channel | Mic input, with I/P = 0 dBu, gain = 0 dB @ 1 kHz input to channel A, channel B output = -85 dB | |
Line Input Response |
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Gain Range | -20 dB to +10 dB in 10 dB steps, plus 0 dB to +20 dB continuously variable trim | |
Input Impedance | 10 kΩ from 10 Hz to 200 kHz | |
Noise | Noise at main output with gain at unity (0 dB) measured with 50 Ω source impedance and a 22Hz – 22 kHz band pass filter | -97 dBu |
Signal-to-Noise Ratio | Measured with 50 Ω source impedance and a 22 Hz-22 kHz band pass filter | 121 dB relative to max output +24 dBu |
Total Harmonic Distortion + Noise | Measured with a 0 dBu input signal, +10 dB of gain and a 22 Hz-22 kHz band pass filter | < 0.002% at 1 kHz |
Frequency Response | At unity gain (0 dB) | -0.3 dB at 10 Hz, -1 dB at 80 kHz, relative to 1 kHz |
Crosstalk Channel to Channel | Line input, with I/P = 0 dBu, gain = 0dB @ 1 kHz input to channel A |
Channel B output = -91 dB |
Instrument Input Response |
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Gain Range | +10 dB to +40 dB continuously variable trim | |
Input Impedance | > 2 MΩ | |
Noise | >Measured with 22 Hz-22 kHz band pass filter | Minimum gain (+10 dB) = -95 dBu |
Frequency Response | At minimum gain (+10 dB) | -0.1 dB at 10 Hz, -1 dB at 115 kHz, relative to 1 kHz |
At maximum gain (+40 dB) | -2.5 dB at 10 Hz, -1 dB at 110 kHz, relative to 1 kHz |
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High-Pass Filter |
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Roll-Off | 18 dB per octave (3 pole filter) | |
Frequency Range | Continuously variable from 16 Hz to 420 Hz (-3 dB) | |
Weight and Dimensions |
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W x D x H | 480 mm x 280 mm x 44 mm | |
Weight | 3.7 kg |