Gain range (Mic)
0 dB to 60 dB in 10 dB steps
ISA 828 incorporates eight of Focusrite's renowned mic pres in a simple-to-operate 2U enclosure, placing eight mic preamps, instrument inputs and line ins at your fingertips. The original Focusrite mic pre was designed to suit the microphones of the time; today's model makes one small change, adding three additional input impedances to the classic ISA 110 setting, allowing you to match any microphone, old or new, and access a wide range of sounds, from the character and warmth of a vintage mic to the clear transparency of a modern design.
Each mic pre has the option of mic, line or the front-panel instrument input, with variable input impedance to ensure you are getting the best performance from the source. Up to 60dB of gain is available on the four-position rotary and gain range switches, with a further +20dB of continuously variable trim, meaning a huge 80dB of gain is available should it be required. The high-pass filter has a fixed 75Hz frequency and 18dB/octave roll-off for minimising rumble, stand-borne noise and other low-frequency sounds. An array of 6-segment LED meters show peak signal level for the four mic pres, in addition to the four direct inputs to the optional A-D card. Switchable rear-panel insert points allow the use of inline processors such as compression.
Gain range (Mic)
0 dB to 60 dB in 10 dB steps
Input Impedance (Mic)
Variable, 600O, 1k4O, 2k4O, 6k8O
Noise at main output with gain at unity (0 dB) (Mic)
-97 dBu measured with a 22 Hz / 22 kHz bandpass filter
Signal to noise ratio relative to max headroom (9dBu) (Mic)
106 dB
THD at medium gain (30dB) (Mic)
0.0008 measured with a 1 kHz -20 dBu input signal and with a 22 Hz / 22 kHz bandpass filter
Frequency response at minimum gain (0 dB) (Mic)
-0.5 dB down at 10 Hz and –3 dB down at 110kHz
Frequency response at maximum gain (60 dB) (Mic)
–3 dB down at 16 Hz and –3 dB down 85 kHz
CMRR (Mic)
91.8 dB (Channel 1, 1 kHz, maxiumum gain)
Input Impedance (Line)
10 kO from 10 Hz to 200 kHz
Gain range (Line)
-20 dB to 10 dB in 10 dB steps
Noise at main output with gain at unity (0 dB) (Line)
-96 dBu measured with a 22 Hz / 22 kHz bandpass filter
Signal to noise ratio relative to max (Line)
120 dB
Signal to noise ratio relative to 0dBFS( 22dBu) (Line)
118dB
THD at unity gain (0dB) (Line)
0.001 measured with a 0 dBu input signal and with a 22 Hz / 22 kHz bandpass filter
Frequency Response at unity gain (0dB) (Line)
0.3 dB down at 10 Hz and –3 dB down at 122 kHz
Gain range (Instrument)
10 dB to 40 dB continuously variable
Input Impedance (Instrument)
1 MO or 300 kO
Noise at minimum gain ( 10 dB) (Instrument)
-90 dBu measured with a 22 Hz / 22 kHz bandpass filter
Noise at maximum gain ( 40 dB) (Instrument)
-62 dBu measured with a 22 Hz / 22 kHz bandpass filter
THD at minimum gain ( 10 dB) (Instrument)
0.002 measured with a 10 dBu input signal and with a 22 Hz / 22 kHz bandpass filter
Frequency Response at 10 dB gain with -10 dB input (Instrument)
10 Hz - 200 kHz /- 0.6 dB
Frequency Response at 40 dB gain with -40 dB input (Instrument)
-2.5 dB down at 10 Hz and 0 dB at 200 kHz
Roll off
18 dB per octave 3 pole filter
Frequency (Instrument)
Fixed 75Hz measured at the 3dB down point
Weight
8.84 kg (19.5 lbs)
Dimensions (W x H x D)
484mm (W) x 85mm (H) x 305mm (D) (350mm depth with heat sink)
