The ISA 430 MKII represents the pinnacle of Focusrite's analog channel strip technology, bringing together all the classic designs in one comprehensive production tool. Augmented with additional features and flavors, 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. Focusrite's ISA 430 MKII adds to the company's iconic status as a leading manufacturer of channel strips.
The design for the ISA preamp goes right back to Focusrite's roots and the original Forte console made for AIR studios. Used on countless professional productions it remains one of the best microphone preamp designs of all time. That's why they haven't changed it, apart from the inclusion of the impedance control for easier use with the range of different microphones available today. Some things simply don't go out of fashion, great sound is one of them.
- Easy visual monitoring with VU and LED meters
- Variable impedance mic preamps for fine-tuning mic input levels
- Flexible signal path provides up to four discrete inputs at once
- Compressor features vintage opto plus Class A design.
- Impeccable EQ drawn from the ISA 110
- The ISA 430 MKII Input Section
The input section on the ISA 430 MKII features a large, professional-grade VU Meter with adjustable calibration, which can be selected to display any one of a number of multiple points in the signal chain. Additional visual monitoring is available through the inclusion of two LED bar graph meters, allowing the signals being fed to the input and output of the unit, or the ADC input levels to be viewed.
As with the ISA 428, the ISA 430 MKII has a variable impedance option on its classic transformer-based mic pre, ranging from 600 to 6800 ohms (at 1kHz). This provides you with increased control over the interaction between microphone and preamp, tailoring the response to suit your needs. Pressing the 'Air' switch further extends this principle, introducing an inductor circuit into the secondary of the transformer, which adds clarity and 'spaciousness' to the signal without the need for EQ.
Flexible Signal Path
The split configurable Inserts and changeable signal path order combine to produce an unrivalled flexibility; herein lies the real benefit of the ISA 430 MKII as a 'do-all' processor for the most demanding of engineers. Both inserts can be used to separate the individual sections of the channel strip. This means that if the post-mic output and ADC inputs are in use, the ISA 430MKII can function as four discrete processors simultaneously! Insert 2 can also be located post-dynamics should this be required, and for further adaptability, the dynamics can be shifted to a pre-EQ or post-sum position.
A significant development from the original ISA 430 can be found in the Compressor section, which now boasts a vintage opto circuit in addition to the original discrete Class A VCA design. Selecting the optical Compressor or Limiter results in a more colored sound, as opposed to the extremely transparent VCA circuit. The ISA 430 MKII caters for the most varied of signals, containing an 'Auto Release' function (switch activated) that changes the release time with each transient to suit the nature of the waveform. If the signal sounds excessively processed, a remedy lies in the Compressor 'Blend' feature, allowing the pre- and post-dynamics signals to be mixed. This can help restore a track's natural dynamism without losing the desired effect of compression.
The ISA 430 MKII features the same classic Focusrite EQ as the original ISA 110, but with two extra frequency values for both the high and low shelving, and with the added benefit of being able to insert the EQ into the sidechain of the Compressor and Gate sections. This allows for fully frequency-conscious compression, gating and expansion, making the ISA 430 MKII the most powerful dynamics processor yet developed.
The Gate section uses the Focusrite Class A VCA as the control element to remove the effect of unwanted interference and high levels of wide-band system noise build-up. Switching this section to expand mode
causes the Gate to function as an Expander. Instead of cutting off any signal below the threshold, an expander proportionately decreases it. This provides a more natural sound when reducing noise from non-percussive sources (especially vocals).
'Hysteresis' increases the level-difference between the gate switching on and switching off, and prevents the gate oscillating ('chattering') with particular combinations of input signal and threshold settings. This function is particularly useful when gating a signal with a very long decay time and large amounts of level modulation (for example a Grand Piano).
The ISA 430 MKII's De-esser is based on a low-distortion optical technology design, allowing transparent removal of excessive sibilance from a vocal performance. The circuit uses phase cancellation to create a smoother and less intrusive de-esser than traditional compression-based designs.
'Listen' to the Difference!
All four dynamic processors; the compressor, gate, expander and de-esser, feature Focusrite's unique 'Listen' feature. Selecting 'Listen', inverts the operation of the processor, so only the chosen frequencies that are being affected can be heard, rather than straining to hear the overall effect in a complex signal.
The sensitively designed soft Limiter, also present in the ISA 428, can be made to act on both the analogue output and the inputs to the optional ADC. The gradual changes in ratio leading up to 0dBFS produce a gentler limiting effect whilst still preventing a level overload.
Optional A/D Card
The optional stereo A/D card provides the ISA 430 MKII with 24-bit 192kHz capabilities and employs the same converters as those featured in the TEC award nominated ISA 428.
- Classic Focusrite transformer-based Mic-pre with variable impedance and 'Air' feature
- Multi format Compressor; switch between Focusrite's transparent VCA circuit and a vintage optical circuit
- Unmatched flexibility with an incredible variety of insert points and variable signal path arrangements
- Ability to function as 4 separate modular processors: mic pre, EQ, Dynamics and stereo ADC
- Precision VU metering of 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
- Post mic pre output for the shortest possible signal path
- Proprietary Focusrite discrete Class A VCA Gate and Expander designs
- 'Listen' feature for precise control over compression, gating, expansion and de-essing
- De-esser design based on optical technology for lower distortion and transparency
- Soft Limiter to avoid critical digital overload
- Optional Stereo A/D - 24-bit 192 kHz Delta Sigma converter