FOCUSRITE ISA 430 MK II MIC PREAMP and PROCESSOR

Overview:

The ISA 430 MKII 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. Focusrite?s iconic status
as the leading manufacturer of channel strips remains unrivalled.

Main Features:
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

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: 100?s 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

Having had great success with the PRE-73 preamp, we have received many requests for a version for the 500 eries rack format. We are therefore happy to present the PRE-573, expected to start shipping in late September.
 
The PRE-573 is a one width module that has the sound and the features that made the PRE-73 so successful and a few additional ones.
The circuit still uses the preamp and output section from the classic 1073-module, adapted to work in the api rack format. It has a total  gain range from -15 to +80 dB. The 10 - 70 dB range is handled by a turn switch  and there is a separate toggle switch to select an additional 5 or 10 dB gain. The input can be configured to accept line level signals by another switch, the gain is then lowered by about 25 dB and the input impedance increased to about 15 kohm.
 
The input impedance of the mic input mode can be switched between 1200 and 300 ohm. Phantom power and phase reverse is also selectable by front panel switches.
 
An added feature, using the same circuit as in the PRE-73 DLX, is the active DI-input with a high input impedance of about 1,5 Mohm. The output signal from the active DI circuit passes through the input transformer for some extra character.
The DI-input is very flexible since it can be changed to a purely passive one by a front panel switch. The DI input is then exactly the same as in the PRE-73 Mk2 where the signal is feed directly into the second gain stage, bypassing the transformer and with an input impedance of about 100 kohm.

These two DI-options makes it possible to get different tones from electric instruments and the passive DI input mode is more suited for injecting active units like sound modules. 
 
A new feature is the switchable AIR mode that  adds a small boost above 10 kHz that peaks at 2 dB at about 35 kHz.

A simple but effective signal and overload indicator is offered by a single LED that starts glowing red at about +4 dBu and then increases its intensity up to the maximum output level.
 
The PRE-573 has a dedicated insert connector at the back allowing it to interface with other GAP 500 modules. The insert can be activated by removing a jumper connector at the back of the module.
The second Golden Age Project module for the api 500 rack will be the EQ-573, expected to ship in November 2012. The EQ-573 consists of the inductor based high pass filter section  and the 3-band eq section from the classic 1073 module with some added frequencies. These two modules together will offer a fully fledged 1073-module in a compact format at a very low cost.
 
There is a second jumper at the back of the module that selects 600 ohm termination on the output. The standard mode is termination on, since it gives the flattest response when the PRE-573 is used with modern line inputs that typically has an input impedance of 10 kohm or more. The user can chose to remove the jumper and deactivate the termination resistor, this will increase the level above 10 kHz and create a peak in the response for an even more pronounced  "Air" effect.
The output is transformer balanced and fully floating and can drive a 600 ohm load up to level of about 28 dBu.

• 1 microphone, XLR (bal.) or 6.3 mm jack (unbal.)
• Gain control, 10 steps (6-50 dB)
• Phantom power can be switched on
• Clip LED
• 1 line output, XLR (bal.) or 6.3 mm (unbal.)
• Operation via supplied power unit

The PRE-73 Mk2 pre-amp and the FC3 condenser microphone in one bundle. The bundle also includes Golden Age P1 Pop Filter, Proel RSM180 mic stand and Proel CHL250 5m cable.

The PRE-73 DLX is a one-channel vintage style microphone-, line- and instrument preamplifier. The signal path uses only discrete components like resistors, capacitors and transistors. The line and microphone input and the line output are transformer balanced, using three different transformers, each one optimized for its purpose.
This is the way audio components were built before integrated circuits became available. The subjective sound quality delivered by vintage equipment is often prefered over the one delivered by modern units, a situation that is even more obvious now when music is recorded with clean-sounding digital audio equipment.

The circuit used in the PRE-73 DLX is similar to the preamp section in the classical 1073 module with a corresponding sound character that is warm, punchy, sweet and musical. These classic characteristics have been heard on countless recordings through the years and it is a versatile sound that works very well on most sound sources and in most genres. The essence of this sound is now available at a surprisingly low cost, making it available to nearly everyone.

FEATURES

- Vintage Style electronics. No intergrated circuits in the signal path.
- Maximum gain on the mic input is 80 dB, enough to handle passive ribbon mics with quiet sound sources.
- Gain range on the Line input: -20 to + 10 dB.
- Switchable impedance on the mic input, 1200 or 300 Ohms, will change the tone of most mics.
- Switchable phantom power and absolute phase.
- A high-impedance instrument input for any sound module, electric guitar or bass.
- A simple but effective 4-step LED output level meter.
- The output level controls makes it possible to make fine gain adjustments and also to overload the main gain stage(s) for more character and then lower the signal to a suitable level before the output stage.
- Combo XLR/TRS input jacks and separate output XLR and TRS jacks for flexible connections.
- Insert jack for inserting EQ´s and other units.
- External high power power supply to avoid interaction with the audio circuits and transformers.
- A solid build quality that will last many years of normal use.

The PRE-73 DLX has a number of improvement and new features compared to the PRE-73 MKII:
- Tantalum capacitors in the signal path.
- Selectable 1073-style high pass filter, 50Hz, 80Hz, 160Hz and 300Hz.
- Output Attenuator -7, -14, -21 and -28 dB (located after the output transformer) allows overdriving the output stage and the output transformer for added character by lowering the output signal to a suitable level.
- The circuit board is prepared for Carnhill Mic and Line transformer and high pass inductor.
- The Insert jack can be switched in/out from the front panel. An internal jumper can select that the Insert jack always has an output signal.
- Switchable 600 ohm Output Termination and Ground Lift on the back panel.
- Selectable Active or Passive DI input and selectable input impedance in active mode, Hi Z or 100 kohm, by internal jumpers.
- The DI can signal can be selected to pass or bypass the mic input transformer by internal jumpers.
- Relays are used to control internal switching for DI input, Phantom power, Mic Low Z, Insert and Phase for shorter circuit board signal paths. The relays are controlled by front panel switches.
- Revised gain switch for added headroom.
- Circuit board star grounding scheme.
- Revised power supply with separate regulators for the audio circuits and relay and LED circuits.