Twin channels of exquisite pre-amplification, with front-panel DI for easy instrument connection.

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The ISA Two is the ideal front-end solution for any studio rack, with two independent channels of Focusrite’s high-quality microphone preamps, each with their own front-panel instrument inputs, so no additional DI boxes are required. Based on the legendary designs found in the Focusrite Forte and Studio Consoles, ISA Two will easily integrate into any audio signal path.

Superb sound spanning four different decades
Focusrite’s microphone preamplifiers go back to the original Focusrite ISA 110 modules, when Rupert Neve was commissioned by George Martin in 1985 to create a no-compromise channel strip for his Neve console. Combining the very best solid-state electronics with transformer coupling, Focusrite mic pres have played a key part in the recording of hundreds of hit records and they’re the choice of leading artists, producers and engineers around the world.

Lundahl Transformers
At the heart of the ISA Two is a pair of Lundahl LL1538 transformers. ISA products have relied on Lundahl from the beginning, since their components were originally specified in 1985. The LL1538 features a 3-section winding, resulting in very low leakage inductance and, as a result, an extended frequency response. They’re encapsulated in mu-metal cans to shield them from stray magnetism.

Variable input impedance and up to 80 dB of gain
ISA Two features two classic Focusrite mic preamps, with four impedance settings including the original ISA 110 setting. Variable input impedance allows you to go for an accurate, transparent sound or choose to highlight the character of your favorite vintage mic – and anywhere in between. With up to 80 dB of low-noise gain, ISA Two can perform in the most demanding situations - really bringing your ribbon, condenser or moving coil mics to life.

Insert your choice of processors
Each channel has a fully balanced insert point accessed via TRS sockets on the rear panel and activated with a front-panel button, so it’s easy to use outboard processors with the ISA Two. Just plug in your choice of EQ, compressor or limiter.

Focusrite ISA Two Classic Dual Mono Transformer-Based Microphone Preamplifier Features:

Lundahl LL1538 mic input transformer maintains flat frequency response across wide bandwidths
Up to 80 dB of clean, distortion-free gain
Four choices of input impedance
User-calibrated metering
Front-panel instrument and rear panel line inputs
Variable cut-off high-pass filter
Rear panel balanced inserts

Focusrite ISA Two Classic Dual Mono Transformer-Based Microphone Preamplifier Specifications:

Front panel, per channel
1/4" Instrument input
Variable input impedance - Low, ISA 110, Medium, High
Input selection - Mic, Line, Instrument
0 - 30 dB/30 - 60 dB gain switch
Phantom power switch
Phase invert switch
0 - 60 dB gain in 10 dB steps
0 - +20 dB continuously variable trim
Variable high-pass filter with on/off switch
Insert point on/off switch
Eight-LED user-calibrated level meters
Single power switch
Rear panel, per channel
XLR-F mic inputs
1/4" TRS line inputs
1/4" TRS Sends
1/4" TRS Returns
XLR-M line output
Single peak meter calibration dial
Single IEC power socket
Maximum Input and Output Levels
Maximum Output Level: +24 dBu with a THD+N < 0.01% at 1kHz measured with 150 O source impedance and 22Hz/22kHz band-pass filter
Maximum Microphone Transformer Input Level: +7 dBu with a THD+N < 0.7% at 1kHz measured at 0 dB of gain with 150 O source impedance and 22Hz/22kHz band-pass filter
Mic Input Response
Gain range: 0 dB to +60 dB in 10 dB steps, plus 0 dB to +20 dB continuously variable trim
Input Impedance: Switched Impedance setting / Equivalent Input Impedance at 1kHz
Low = 600 O
ISA 110 = 1.4 kO
Med = 2.4 kO
High = 6.8 kO
EIN (Equivalent Input Noise): Measured at 60 dB of gain with 150 O source impedance and 22 Hz-22kHz band pass filter = -127 dB
Noise: Noise at output with unity gain (0 dB) and 22 Hz-22kHz band pass filter = -97 dBu
Signal-to-Noise Ratio: Measured with 150 O source impedance and 22 Hz-22kHz band pass filter = 121 dB relative to max output +24 dBu
Total Harmonic Distortion + Noise: Measured with a -20 dBu input signal at +30 dB of gain and with a 22 Hz-22 kHz band pass filter = < 0.0007% at 1kHz
Frequency Response:
At minimum gain (0 dB)
-0.5 dB at 10 Hz, -1 dB at 135kHz, relative to 1kHz
At +60 dB gain
-6 dB at 10 Hz, -1 dB at 115kHz, relative to 1kHz
CMRR (Common Mode Rejection Ratio):
-94 dB for mic input at 60 Hz for max. output = +24 dBu
-91 dB for mic input at 10 kHz for max. output = +24 dBu
Crosstalk Channel to Channel: Mic input, with I/P = 0 dBu, gain = 0 dB @ 1kHz input to channel A, channel B output = -85 dB
Line Input Response
Gain Range: -20 dB to +10 dB in 10 dB steps, plus 0 dB to +20 dB continuously variable trim
Input Impedance: 10 kO from 10Hz to 200kHz
Noise: Noise at main output with gain at unity (0 dB) measured with 50 O source impedance and a 22Hz - 22 kHz band pass filter = -97 dBu
Signal-to-Noise Ratio: Measured with 50 O source impedance and a 22Hz-22kHz band pass filter = 121 dB relative to max output +24 dBu
Total Harmonic Distortion + Noise: Measured with a 0 dBu input signal, +10 dB of gain and a 22Hz-22kHz band pass filter = < 0.002% at 1kHz
Frequency Response:
At unity gain (0 dB) -0.3 dB at 10Hz, -1 dB at 80kHz, relative to 1kHz
Crosstalk Channel to Channel: Line input, with I/P = 0 dBu, gain = 0dB @ 1kHz input to channel A
Channel B output = -91 dB
Instrument Input Response
Gain Range: +10 dB to +40 dB continuously variable trim
Input Impedance: > 2 MO
Noise: >Measured with 22Hz-22kHz band pass filter = Minimum gain (+10 dB) = -95 dBu
Frequency Response:
At minimum gain (+10 dB)
-0.1 dB at 10 Hz,
-1 dB at 115 kHz, relative to 1 kHz
At maximum gain (+40 dB)
-2.5 dB at 10 Hz,
-1 dB at 110 kHz, relative to 1 kHz
High-Pass Filter
Roll-Off: 18 dB per octave (3 pole filter)
Frequency Range: Continuously variable from 16 Hz to 420 Hz (-3 dB)
Weight and Dimensions
Dimensions (WxHxD): 18.90” x 1.73” x 11.02” (480 mm x 44 mm x 280 mm)
Weight: 8.16lb

Focusrite ISA Two Classic Dual Mono Transformer-Based Microphone Preamplifier

All Focusrite products are built to the highest standards and should provide reliable performance for many years, subject to reasonable care, use, transportation and storage.

In the event of a Manufacturing Defect becoming evident within 12 months from date of purchase Focusrite undertakes that the product will be repaired or replaced free of charge if the product is returned to the authorised dealer from whom it was purchased. In these circumstances, or if you need an out-of-warranty repair to your Focusrite product, please contact your local Focusrite distributor in your country of residence or business : Find your local distributor here and you will be advised of the correct return procedure.

Alternatively contact the Focusrite Reseller from which you purchased the product. If you purchase a Focusrite product outside your country of residence or business you will not be entitled to ask your local Focusrite Distributor to honour this Limited Warranty, although you may request a chargeable repair.

Alternatively, the unit may be returned at your cost to the dealer you purchased the unit from so that they can organise a Warranty repair with their Focusrite Distributor.

This Warranty does not include cost of shipping to and from the authorised dealer from whom it was purchased. In every case it will be necessary to provide the original invoice or store receipt to accompany the defective product to the supplying dealer. This Limited Warranty is offered solely to the first purchaser of the product from an Authorised Focusrite Reseller (defined as a reseller which has purchased the Product directly from Focusrite Audio Engineering Ltd. in the UK or its Authorised Distributors outside the U.K,) and is not transferable.

This Warranty is in addition to your Statutory Rights in the country of purchase.

Please note: A Manufacturing Defect is defined as a defect in the performance of the product which may be expected from a reasonable interpretation of the published description and performance specifications as published by Focusrite Audio Engineering Ltd. This does not include damage caused by post-purchase transportation, storage or careless handling, nor damage caused by misuse.

A significant proportion of products returned under Warranty (which are very few in number compared to numbers sold) are found not to exhibit any fault at all. Please check that the mains voltage is correctly set for your local supply and that your connecting cables are in good order and correctly connected.

If in doubt about the product functions please read the user guide and if necessary contact your dealer for advice before returning the product to the supplying dealer. You can also contact the Focusrite Tech Support team at the Focusrite Answerbase for general advice.

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