Focusrite ISA430 Mk II Channel Strip

The Focusrite ISA430 Mk II Channel Strip represents the pinnacle of Focusrite’s analogue channel strip technology, bringing together all the classic designs in one comprehensive production tool. Augmented with additional features and flavours, alongside unmatched internal routing and connectivity, the ISA 430 MkII enables today’s recording professional to enjoy the unique sonic contribution of these heritage designs within one extremely versatile processor. With the Producer Pack, Focusrite’s iconic status as the leading manufacturer of channel strips remains unrivalled.

 Left Front

Focusrite ISA430 Mk II Channel Strip Features:
-ISA-series transformer-based pre-amp
-Featuring mic impedance switching and unique ‘mic air’ effect (a wire-wound inductor for increased spaciousness).
-Dual topology compressor:  The ISA 430 MkII is the first ISA to feature both the classic transparent VCA circuit, and avintage optical
  circuit with both soft compression and crunch settings.
-Unmatched flexibility:  The ISA 430 Mk II features an incredible variety of insert points and variable signal path arrangements. It can
  operate as four independent modules
-Precision VU metering at multiple points:  Including input level, Insert 1 or 2 Return level, Compressor gain reduction or Sidechain listen
  level (switched).
-Classic Focusrite EQ design:  an expanded version of the original ISA 110 with two additional shelving positions.
-Gate and Expander:  Proprietary Focusrite discrete Class A VCA Gate and Expander designs, now both featuring a 'Listen' option for
  precision control.
-De-esser featuring 'De-ess Listen':  A combination of EQ and phase cancellation are used to create a smoother and less obtrusive result.
-Optional Strereo 192kHz ADC:  Embodies cutting-edge conversion technology, incorporating Focusrite analogue circuitry to deliver A/D
  conversion of the highest quality (120dB Dynamic range).  Add the card using the drop-down box at the top of this page

 Right Front

From mic impedance switching and ‘mic air’ effect (a wire-wound inductor for increased spaciousness), to three compressor options (VCA, Vintage Opto and Opto Limit) combined with the compressed/uncompressed ‘Blend’ feature, the ISA430 MkII delivers a impressive variety of processing sounds.

 
Optional AD Card, sold separately

Routing and monitoring flexibility has also received a booster. The unique ‘Listen’ feature (allowing you to hone in on the frequency you wish to affect) is now available on compressor, gate, and expander circuits as well as the ISA 430 MkII’s unique phase cancellation-based de-esser circuit. In addition, monitoring and inserts are available at a variety of points along the signal chain. Finally, the ISA 430 MkII features an optional 24bit-192kHz high performance (122dB A-weighted with jitter below 20 pico seconds) stereo A-D converter, allowing you to retain every nuance of your analogue signal as you flow seamlessly into the digital domain.

 Rear

The Focusrite design for the original ISA110 EQ was commissioned as a custom rack for Air Montserrat, and later at George Martin’s personal request, for the custom Neve at Air London, (these units are still working at Air Lyndhurst today.) But what makes the Focusrite EQ so special?

The design, like most great designs, is relatively simple; a classic six band EQ, with shelving high and low bands, parametric low mid and high mid bands, and low and high pass filters. The HF and LF shelving EQ’s are unique – they are an implementation of the legendary Baxandall circuit designed in the 1950’s. The EQ is inherently expensive to build as a circuit; most typical shelving filters are variable resistance, fixed capacitance, but the design featured instead variable resistance for gain and variable capacitance for frequency. The positive benefit of this high-end design is that there is no interrelation between EQ bands, (making a change to one band has zero effect on another band,) and that the EQ is virtually noiseless.

The HF and LF EQ features switched capacitor circuits, rather than a variable resistor circuit. (The shape of the shelving filter in the case of a variable resistor circuit varies according to the frequency, thus shelving response is not pure, it’s shallow at one point, steep at another.) With the ISA 110, this switched capacitor circuit means the Q is constant, and the EQ slope is constant, meaning accurate, predictable, beautiful results.

The high-mid and low-mid EQ bands are fully parametric, and are a full implementation of the state variable circuit configuration – separate amplifiers for the Q, and for low-mid/high-mid gain. The usual cheap way to simulate this is to implement a compromise – a gyrator mid-band peaking circuit – but cutting corners in this way invariably means a poor imitation of the real thing. The Focusrite way has, from the beginning, been to choose the solution that sounded best then minimise cost through elegant design.

Focusrite ISA430 Mk II Channel Strip Specifications:
-Line
  -Gain Range: +10dB to +40dB continuously variable
  -Input Impedance: >1M Ohm
-Mic
  -Gain Range: 0 to +60dB in 10dB steps
  -Input Impedance: Variable as follows: 600 Ohm, 1k4 Ohm, 2k4 Ohm, 6k8 Ohm
  -EIN: -128dB with 150 Ohm terminating impedance at 60dB of gain
  -Noise: -97dBu
  -THD: 0.001% with -20dBu 1kHz input and 20Hz?22kHz bandpass filter
-Compressor (VCA mode)
  -Threshold Range: -28dB to +12dB
  -Ratio: 1.5:1 to 10:1
  -Slope: Soft knee
  -Attack: 100µs to 100ms
  -Release: 100ms to 7s, variable or auto (program dependent)
-Compressor (Vintage Opto mode)
  -Threshold Range: -28dB to +12dB
  -Ratio: 1.5:1 to 5:1 in Comp mode, 5:1 to 20:1 in Lim mode
  -Slope: Soft knee in Comp mode, Hard knee in Lim mode
  -Attack: Fixed
  -Release: Fixed
-EQ
  -Low Pass Filter: 18dB/oct from 400Hz to 22kHz
  -High Pass Filter: 18dB/oct from 20Hz to 1k6Hz
  -Parametric section is comprised of: Low-mid & Hi-mid parametric, each with continuously variable boost/cut with centre detent, frequency
    sweep control with two ranges, and fully variable Q. Low-mid frequencies 40Hz to 400Hz (120Hz to 1k2Hz when x3 is pressed). Hi-mid
    frequencies 600Hz to 6kHz (1k8Hz to 18kHz when x3 is pressed)
  -Shelving section is comprised of: High Frequency Shelf: The frequency range steps are 1.5kHz, 3.3kHz, 6.8kHz and 15kHz (2.2kHz,
    4.7kHz, 10kHz and 18kHz when Hi Range is engaged). Low Frequency Shelf: The frequency range steps are 20Hz, 56Hz, 160Hz and
    460Hz (33Hz, 95Hz, 270Hz and 655Hz when Hi Range switch is engaged)
-Gate
  -Threshold Range: -40dB to +10dB
  -Gate Range: 0 to -80dB
  -Attack: switched fast or slow
  -Release: 100ms to 5s
  -Hold: 20ms to 4s
  -Expander Ratio: 0 to 5:1
-De-Esser
  -Threshold Range: 22dB
  -Frequency Range: 2k2 to 9k2
  -Ratio at centre frequency: 2:1
-Limiter
  -Threshold Range: 20dBu
  -Ratio: infinite (Brick Wall)
  -Attack: Frequency dependent
-Dimensions
  -484mm (W) x 85mm (H) x 250mm (D)
  -19" (W) x 3.5" (H) x 9.8" (D)

Optional 9-pin cables also available.  Choose from AES/EBU, SPDIF, or get both.  Add the one you want from the drop down box at the top of this page.  The price will change to reflect your choice.