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Posted on March 21, 2013 by Tony Long There have been 0 comments

Focusrite ISA Two Dual Mic PreampYou can read more reviews like this, listen to Tony’s productions, purchase synth patches and more at his personal site -> Tony Long Music.


I haven't reviewed a Focusrite preamp before but there are many people out there who shout about how good their ISA One preamp (introduced in 2008) is. The ISA One is undeniably a fantastic single preamp, designed to be very portable with its compact design and carrying handle. It has been some years coming but to cater for the people that really wanted two preamps to record in stereo for example, Focusrite announced the ISA Two dual-mono mic preamp at Musikmesse 2012. With the design of the ISA Two, Focusrite went for a rackmount unit, providing two independent channels with those classic mic preamps.

Focusrite ISA Two Dual Microphone Preamp


The ISA Two is a solid 1U rack unit and weighs 3.7 kg. It looks very smart and colourful as you take it out of the box and it has retained the same colour scheme as the ISA One (blue and grey with yellow caps on four out of the six knobs). Once it's fired up and displaying its LEDs it all looks very professional and will certainly brighten up your studio rack. The ISA Two comes complete with an IEC power cable and a small but nevertheless very useful manual in English, French and German. It will not take you long to read through its eighteen pages.


The Focusrite ISA Two has variable input impedance, providing four different values for the mic input, including the famous ISA 110 value. This is so that you can really get the best out of any microphone, whether it is a condenser, ribbon or dynamic mic. There is also an input selector for Mic, Line and instrument inputs. You get a fantastic amount of gain up to 80 dB with the ISA Two. This is shared between the transformer input (which is a Lundahl LL1538 transformer) and the circuitry. The transformer instantly provides 20 dB of gain and the other 60 dB comes from the circuitry. Despite this amount of gain it has a very low noise floor.

Focusrite ISA Two Dual Preamp


There is not much to learn when it comes to understanding the front panel of the ISA Two because as it is a dual channel preamp, once you know half of it, you practically know it all! On the left-hand side it starts with two quarter inch instrument inputs; one per channel to connect high impedance instruments such as electric guitars and basses. It is very handy having these at the front of the rack and no DI box is needed.

You then have two selector buttons with seven LEDs and there is a repeat of this further along for channel two. The first selector button allows you change the variable input impedance. You can select from four different values: Low (600), ISA 110 (1.4k), Medium (2.4k) or High (6.8k). This is probably one of the best features on the ISA Two. You then have an Input selector button to select your input from Mic, Line or Instrument.

The next section on the grey background is for channel 1 only and consists of 5 buttons and 3 large dials. Again, there is a repeat of this section for channel two. The first button is a 30-60 dB switch, which allows you to select the range of the gain control from either 0 to +30 dB or +30 to +60 dB. It is set with a default range of 0 to +30 dB. You then have the phantom power button, which gives +48V to the mic input on the back panel for use with condenser mics. The third switch button inverts the phase signal.

We then come to the three large white dials, which are very solid and precise, making it easy to dial in your own settings. The first deals with setting the gain of the input signal in steps of 10 dB and there are different printed indicators around the dial to cater for use with both a microphone and a line level signal. The next control is a Trim dial, which gives you an additional 20 dB to a mic/line-level signal, or it can be used to add extra gain for the instrument inputs. The last dial is for the variable high-pass filter. Here you can select the frequency of the filter from 16 Hz to 420 Hz.

This just leaves two buttons: one filter switch to activate the filter and an Insert point on/off switch, allowing you to send your signal to additional external processors before it is output. This is done by using the Send and Return connectors on the back panel. After the channel two section, there is simply the eight-LED output/peak user-calibrated level meters that show the output values in dBFS for both channels (and of course the power switch). All in all it should not take you too long to get to grips with.


It is a similar story around the back of the ISA Two, where, apart from the IEC mains lead input and the Peak Meter Calibration dial, it is divided into two sections with connections for Channel 1 and 2. For both channels there are female XLR mic inputs; balanced quarter inch line, send and return inputs and male XLR outputs. With the send and returns you can quickly add in your favourite external effect processors as each channel has a fully balanced insert point. You can connect your choice of compressors, limiter and EQ etc. Sadly, there is no digital output but no doubt this would have increased the price somewhat. The 'Peak Meter Calibration' dial, as it says on the can, allows you to calibrate the meters on the front panel. This means that you can line up the ISA Two pres and the metering with your interface or with your analogue system and you can build in headroom. In this last example, you could therefore know that even though your red light is coming on, it is actually, for example, 6 dB less - what a great idea. It is worth noting that the Focusrite ISA Two has a global power supply, so all you need is an IEC cord with the appropriate plug for the particular country's supply.

Focusrite ISA Two Dual Microphone Preamp - Connections


I have been working with a lot of vocals recently, so I thought I would experiment by comparing how the ISA Two measures up to my TC Konnekt interface, which I have to admit has some very nice Impact II preamps.

After listening to the results, there seems to be a nicer sheen and quality to the recordings from the ISA Two. It has a warmer sound, which is partly to do with the quality of the input transformer.

I also tried altering the variable input impedance for different vocal takes. As I have said, there are four to choose from, one of which is the very famous ISA 110, which is renowned for getting the best out of any mic whether it be a condenser, dynamic or ribbon. I found that changing the input impedance was better than changing the mic as I achieved a much warmer sound with more body, character, shine and smoothness, which was very flattering. The sound is also remained 'open' with very low noise level. You really get a quality sound here for your money and I seemed to be using the variable input impedance more like an EQ because of the tonal variation that it produced.

The ISA 110 apparently comes from way back in good old 1985 when George Martin commissioned Rupert Neve to create a channel strip. It had an ISA 110 mic preamp and this is what started the ISA Series, which of course is still with us today.

So, to sum up, I concluded that I much preferred the vocal takes made with the Focusrite ISA Two!

I know it has been named a 'dual mono mic pre' but there is no button or switch to select a stereo recording or to join the two channels together in some way, but I understand that the channels are well matched in this respect. I did however find that it is very easy to match the gain of the two channels from the front panel, and if you want to make some finer adjustment you also have the trim control. This is different from the Focusrite ISA One (and it can be slightly confusing), which is a stereo recording device with one mic preamp that has a simultaneous DI, whereas the DI on the ISA Two is not simultaneous.


When it comes to preamps, there is a fair bit of competition, but at this price level I don't think there is anything out there to compete with the extras that you get with the Focusrite ISA Two. To a large extent it is an obvious choice that does not really have any limitations. If you consider that they have taken the preamp out of their high-end, more expensive channel strips and made it extremely affordable, it is not a difficult choice to make. Perhaps the statement at the back of the unit explains why the cost is so good when it says 'Designed in England - Made in China'.

The Focusrite ISA Two occupies a single rackspace, looks colourful and professional, has Lundahl LL1538 mic input transformers, it offers up to 80 dB of clean, distortion-free gain, it gives you four choices of variable input impedance, you get user-calibrated metering, a built-in and extremely smooth-sounding 18 dB/octave high-pass filter, front-panel instrument and rear panel line inputs and rear panel balanced inserts. Can you really ask for more? Well, yes: it has got to sound great and it luckily it does with so much more! If you only need a couple of preamps then you will most certainly want to have something a bit special and in my opinion the ISA Two is an excellent option.

If however, you are looking for something to add real colour to your sound, then I would say that this is not for you as the ISA Two provides what I would describe as a quality, un-coloured, clean and punchy sound. Lastly, if you really only need one preamp and would like something more portable, then I would recommend the Focusrite ISA One. I think both of these products will stand the test of time and you will find them in many studios around the world from home to professional.

Don't forget that throughout March and April 2013, you can make HUGE savings on the Focusrite ISA Two! CLICK HERE for more information on this offer!

Also.... don't miss out on the Focusrite/Novation/KRK daily £200 giveaway until 10th May 2013! The sooner you enter the more chance you have of winning more gear! Click here for more information.

For more information on the Focusrite ISA Two, click the link below or give us a call on 01202 597180.

Focusrite ISA Two - More Info/Buy

Click To Buy Focusrite ISA Two Dual Mono Microphone Preamp

Focusrite ISA One - More Info/Buy

Click To Buy Focusrite ISA One Preamp

Focusrite ISA One with Digital Card Bundle - SAVE £££s!!! - More Info/Buy

Click To Buy Focusrite ISA One & Digital Card copy

Focusrite ISA 428 MkII - More Info/Buy

Click To Buy Focusrite ISA 428 MkII Preamp

Focusrite ISA 828 - More Info/Buy

Click To Buy Focusrite ISA 828 Preamp

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This post was posted in Blog entries, General News, In-Depth Reviews, Product News, Recording and was tagged with dual mic preamp, focusrite, focusrite isa two, isa two, mic preamp