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ISA 828
Eight classic microphone preamplifiers and class-leading A-D conversion

Specifications

We always quote 'real world' performance figures (measured to the AES17 standard). Some companies choose to quote chipset performance, which is misleading, and here's why.

Mic Input Response

  • Gain range: 0dB to 60dB in 10dB steps
  • Input Impedance, variable: 600Ω, 1k4Ω, 2k4Ω, 6k8Ω
  • 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: 10k? 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: 1M? or 300k?
  • 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

Weight

  • 8.84kg
  • 19.5Ibs

Dimensions

  • 484mm (W) x 85mm (H) x 305mm (D) (350mm depth with heat sink)
  • 19" (W) x 3.5" (H) x 12" (D) (13.8" depth with heat sink)