Focusrite ISA 428 Pre Pack Microphone Preamp

Focusrite ISA 428 Pre Pack Microphone Preamp
The ISA 428 Pre Pack is the perfect multi-channel front end for any professional DAW. Four classic, Rupert Neve-designed, transformer-based pre amps with switchable impedance and direct instrument inputs. An optional eight channel 192kHz ADC, preceded by the all new proprietory Soft Limiter circuit, provides the perfect path into your Pro Tools HD system.

The benefits of the pre amp's topology include superb common-mode rejection, an excellent overload margin and, with its shared gain structure (20dB from the hand-wound transformer and up to 40dB from the amplifier), an extremely low noise floor and super-wide bandwidth (10Hz to 200kHz). This pre amp design is the cornerstone of Focusrite's signature 'warm-yet-transparent' sound and is a point of reference for any discerning audio professional.

In addition, the input stage provides enhanced control and creativity allowing you to switch between four carefully selected input impedance settings. The original ISA 110 setting is supplemented by three further impedance settings to either perfectly match the pre amp with any microphone and maximise level, or use different settings creatively to shape the sound of the microphone being used. Should the need arise to place extra processing in between pre amp and conversion, insert points are also featured on every channel.

Protecting the ADC, the Soft Limiter opto circuit is a new design from Focusrite, entirely preventing any 'digital overs', whilst minimising the undesirable distortion that standard limiter circuits often generate.

Finally, the new ADC embodies cutting-edge conversion technology, encompassed within pristine Focusrite circuitry, providing eight conversion channels of the highest quality, at frequency rates of up to 192kHz. Running at 96kHz allows for up to 16 (2 x 8, parallel) simultaneous digital outputs in addition to the four main analogue outputs. Digital output options include dual AES/EBU, SPDIF and dual ADAT lightpipe. Full digital metering is provided for every channel, alongside new 'moving coil' peak meters, designed to catch even the fastest of transients.

A second analogue unit can be connected utilising the four extra ADC input channels on the rear of the unit containing the optional ADC. This makes full use of the eight channels provided on a single optional ADC and expands your front-end capacity from four pre amps and eight digital outputs to eight Pre amps and eight digital outputs.

Classic preamp technology, custom Focusrite input and limiting circuits and the very best in A/D conversion technology, the ISA 428 Pre Pack raises the bar for multi-channel recording solutions into Pro Tools HD, or any other professional DAW. Equally, it can be used as an additional set of high quality pre amps for any analogue or digital console or hard disk recorder.

Highlights

• Four classic Rupert Neve-designed transformer-based preamps.
• 8 channels of cutting-edge A/D conversion, running at up to 192kHz. Protected by proprietory optical Soft Limiter circuit.
• Switchable Impedance for unparalleled mic matching or extended mic creativity - includes the classic ISA 110 setting.
• Multiple Front Panel Instrument DI. No separate DI box required.
• Analogue insert points on every channel.
• Rupert Neve-designed High Pass Filters on every channel.
• New moving coil peak meters & full digital metering (dBfs).

Gain range: Line = +/- 18dB; Mic = 0 to 60dB (both in 6dB steps); Inst = +10 to +40 dB variable
Input impedance: Line = 10k ohm; Mic = Variable - 600, 2k4 and 6k8 ohm + original ISA 110 settings; Inst = >1M ohm

Analogue Performance
Noise: Line = -96dB; Mic = -128dB (EIN with 150 ohm input resistance at 60dB of gain)
THD: Line = 0.003% with 0dBu, 1kHz input and 20Hz to 22kHz band-pass filter; Mic = 0.003%

Analogue Input and Output connectors (balanced)
D.I inputs: 1/4 inch Jack (unbalanced)
Mic inputs: XLR (balanced)
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