FOCUSRITE ISA 428 FOUR CHANNELS MIC PREAMPLIFIER

Overview:

The ISA 428 Pre Pack is the perfect multi-channel front end for any professional DAW.
Four classic Focusrite 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.
Four classic Focusrite 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.
High Pass Filters on every channel.
New moving coil peak meters & full digital metering (dBfs).

ADAT is a trademark of Alesis Corp
Pro Tools HD is a trademark of Avid Technologies plc.
The 192kHz ADC is an extra cost option.

Specifications
Inputs
Transformer-based ISA design
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)
Line: TRS Jack (balanced)
Insert Sends and Returns: TRS Jack (balanced)
Additional ADC inputs: XLR (balanced) Line level
Analogue Outputs: XLR (balanced)

Digital Output Option
AES/EBU and S/PDIF dual 9-pin D-types
Optical - ADAT Lightpipe
Bit depths 16-, 20- or 24-bit
Frequency options 44.1, 48, 88.2, 96, 176.4 and 192kHz
Clock options Standard or ?256 x?
Meter - 0 dBFS = +22dBu
Digital Performance
SNR - 120dB A-weighted

PreSonusʼ popular Class A XMAX preamps are widely lauded for their clarity and transparency. Our tube preamps are beloved for their warm, smooth sound. With the Blue Tube DP V2 dual-path mic/instrument preamp, you get both types of high-quality sound in one unit.

Now weʼve improved on the classic unit with the BlueTube DP V2. The solid-state path now feeds PreSonusʼ top-of-the-line Class A XMAX™ mic preamplifier with 80 dB of variable gain—an upgrade from the original BlueTube DPʼs solid-state stage.

You still get all the secondary features you expect in a professional-grade preamp: 48V phantom power, an 80 Hz high-pass filter, -20 dB pad to control hot input signals, and a polarity-reverse switch. Each channel has an illuminated VU meter so you can visually monitor your input levels.

A Tube Drive control provides a wide range of sounds: when itʼs clicked off, youʼre using the solid-state preamp for quiet, transparent amplification; when itʼs engaged, your signals flow through the tube preamp, and you can achieve anything from gentle warmth to edgy distortion.

    2 input channels, each with:
        High-headroom Class A XMAX™ mic preamplifier with 80 dB gain range
        12AX7 vacuum tube gain stage
        Tube Drive tube-saturation control
        48V phantom power
        80 Hz high-pass filter
        -20 dB pad to reduce hot input levels
        Polarity-reverse switch
        Illuminated analog VU input-level meter

    Input/Output
        2 balanced combo mic/unbalanced instrument inputs
        2 balanced XLR main (L/R) line outputs
        2 unbalanced ¼” main (L/R) line outputs

    Physical
        Compact 1/2U chassis
        External 12 VDC, 1A power supply

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 Mk2 is the first one-channel low-cost preamp on the market that is using a fully discrete signal path with three separate transformers for the balanced mic input, the line input and the output.

The circuit is very similar to the classical preamp section of the Neve 1073 pre/eq module with a corresponding sound character that is warm, punchy, sweet and musical.
This classical sound has 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 PRE-73 Mk2 has a maximum gain of 80 dB on the mic input and the gain range on the Line input is -20 to + 10 dB. There is also a high-impedance instrument input.

The PRE-73 Mk2 is perfect for almost any signal source, no matter if it's a microphone with a high or low sensitivity (like a passive ribbon mic), a syntheziser or sound module or an electric guitar or bass.

The input impedance of the microphone input can be switched between 300 and 1200 ohms, which makes it possible to affect the tone of most microphones. There is also phase switch and an simple 4-step LED signal level meter.

The output level control makes it possible to make fine gain adjustments and also to overload the main gain stage for more character and then lower the signal to a suitable level before the output stage.

The Mk2 update consists of:
- An unbalanced insert jack (nominal level about 18 dBu) added on the back panel for inserting units like the coming GAP EQ-73, a three band eq.
-  LED meter levels adjusted.
- 600 Ohm termination resistor and jumper added to power supply board (accessible from the inside of the unit).
- Revised Gain switch, turning the know clockwise now increase the gain.
- Reduced noise at high gains by a change to the power supply grounding scheme.

The PreSonus HP60 is the most flexible and advanced headphone amplifier system available for professional and project recording studios as well as live sound in-ear monitoring systems. Loaded with six independent,
loud and clear headphone amplifiers, the HP60 features dual stereo inputs as well as external input, for each
channel allowing you to mix between three stereo audio streams (mix A, mix B, and external input). Stereo output is also available on each channel to send line level headphone channel mixes to additional headphone amplifiers or monitor systems. Each channel features headphone level, mix control between A and B inputs, external input volume, mute and mono. The HP60 also features talkback via external XLR microphone input. Common set up of the HP60 in a recording session is to send the main control room mix to input A. Send the click track to input B. Send the each band member direct recording input to each channelʼs external input (more me). This will allow each band member to create a mix between the main mix, the click track and themselves. The HP60 is the ultimate headphone amplification system delivering loud and clear headphone mixes for real-world recording situations.

Features:
-Six independent ultra low noise, high output headphone amplifiers (150 mW per channel)
-Two sets of stereo inputs (A and B) with balanced TRS connectors
-Stereo external input point on each channel for "more me” with trim control
-Mix control between inputs A and B
-Talkback with external XLR microphone with control
-Direct stereo line output on each channel