ISA430 MkII

• ISA-series transformer-based pre-amp
  Featuring mic impedance switching and unique ‘mic air’ effect (a wire-wound inductor for increased spaciousness).
• Dual topology compressor
  The ISA 430 MkII is the first ISA to feature both the classic transparent VCA circuit, and avintage optical circuit with both soft compression and crunch settings.
• Unmatched flexibility
  The ISA 430 Mk II features an incredible variety of insert points and variable signal path arrangements. It can operate as four independent modules!
• Precision VU metering at multiple points
  Including 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 with two additional shelving positions.
• Gate and Expander
  Proprietary Focusrite discrete Class A VCA Gate and Expander designs, now both featuring a 'Listen' option for precision control.
• De-esser featuring 'De-ess Listen'
  A combination of EQ and phase cancellation are used to create a smoother and less obtrusive result.
• Optional Strereo 192kHz ADC
  Embodies cutting-edge conversion technology, incorporating Focusrite analogue circuitry to deliver A/D conversion of the highest quality (120dB Dynamic range).

• Rear

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. With the Producer Pack, Focusrite’s iconic status as the leading manufacturer of channel strips remains unrivalled.

From mic impedance switching and ‘mic air’ effect (a wire-wound inductor for increased spaciousness), to three compressor options (VCA, Vintage Opto and Opto Limit) combined with the compressed/uncompressed ‘Blend’ feature, the ISA430 MkII delivers a impressive variety of processing sounds.

Routing and monitoring flexibility has also received a booster. The unique ‘Listen’ feature (allowing you to hone in on the frequency you wish to affect) is now available on compressor, gate, and expander circuits as well as the ISA 430 MkII’s unique phase cancellation-based de-esser circuit. In addition, monitoring and inserts are available at a variety of points along the signal chain. Finally, the ISA 430 MkII features an optional 24bit-192kHz high performance (122dB A-weighted with jitter below 20 pico seconds) stereo A-D converter, allowing you to retain every nuance of your analogue signal as you flow seamlessly into the digital domain.

The Focusrite design for the original ISA110 EQ was commissioned as a custom rack for Air Montserrat, and later at George Martin’s personal request, for the custom Neve at Air London, (these units are still working at Air Lyndhurst today.) But what makes the Focusrite EQ so special?

The design, like most great designs, is relatively simple; a classic six band EQ, with shelving high and low bands, parametric low mid and high mid bands, and low and high pass filters. The HF and LF shelving EQ’s are unique – they are an implementation of the legendary Baxandall circuit designed in the 1950’s. The EQ is inherently expensive to build as a circuit; most typical shelving filters are variable resistance, fixed capacitance, but the design featured instead variable resistance for gain and variable capacitance for frequency. The positive benefit of this high-end design is that there is no interrelation between EQ bands, (making a change to one band has zero effect on another band,) and that the EQ is virtually noiseless.

The HF and LF EQ features switched capacitor circuits, rather than a variable resistor circuit. (The shape of the shelving filter in the case of a variable resistor circuit varies according to the frequency, thus shelving response is not pure, it’s shallow at one point, steep at another.) With the ISA 110, this switched capacitor circuit means the Q is constant, and the EQ slope is constant, meaning accurate, predictable, beautiful results.

The high-mid and low-mid EQ bands are fully parametric, and are a full implementation of the state variable circuit configuration – separate amplifiers for the Q, and for low-mid/high-mid gain. The usual cheap way to simulate this is to implement a compromise – a gyrator mid-band peaking circuit – but cutting corners in this way invariably means a poor imitation of the real thing. The Focusrite way has, from the beginning, been to choose the solution that sounded best then minimise cost through elegant design.

Q: What are the key features?
A: -Many types of class A dynamic and EQ processing in one box
-Focusrite-Quality audio throughout, eg Huge bandwidth: 10Hz-200kHz
-Focusrite professional Mic Pre with variable input impedance
-Mic-pre features an inductor circuit to naturally boost HF response
-Original ISA110 EQ with additional shelving frequencies
-Multi format compressor; Focusrite?s transparent VCA circuit and vintage optical circuitry
-Original ISA130 Class A Expander/Gate
-Opto. de-esser utilizing phase-cancellation de-ess technology
-Opto-circit Soft Limiter
-Optional 24 bit/192kHz digital output board
-Unparalleled routing flexibility, including a variety of insert points and variable signal path order
-Able to be used for tracking, mix-down or as stereo A/D

Q: Are the EQ and Dynamics the original Rupert Neve/Focusrite designs ?
A: Yes; the Mic Pre, Hi- and Lo- pass filters, EQ, Compressor, and Expander/Gate are all based on those used in the original Neve-designed Focusrite console. However, the circuitry has been expanded to incorporate new features; the ISA 110 EQ having additional frequency options for its shelving and the compressor now including opto-circuitry and extra routing and controls. Plus, the mic-pre has a variable impedance and new selectable 'air' effect.

Q: Is the ISA430 MK II a Class A device, and why is that important?
A: Yes, the 430 MK II is a Class A device. Why? Well, Class A is a type of amplifier design in which you have a standing DC current running through your amplifier circuits all the time. As the signal comes along you vary what you're taking from that, rather than switching between supplying a positive current for one half of the waveform and a negative current for the other half. This results in the ability to represent audio in a linear (distortion free) manner all the way through the circuit. Cheaper processors use IC amplifiers which run close to Class B and don't have the same standing DC current, which means the transistors inside the chips switching off and on, inevitably resulting in less linear performance.

Q: What does the 'Vintage' compressor button involve?
A: In addition to the class A VCA circuit, the vintage optical circuit adds a whole new flavour of compression. The vintage circuit operates in two modes, as a compressor character or as a limiter. The attack and release are fixed when using the opto-circuit and the threshold point is raised/the knee hardened when compressing with the limiting characteristics selected.

Q: So the compressor contains VCAs and optical technology?
A: Yes. Whilst the Expander and Gate use solely VCAs and the De-esser and Limiter are optical.

Q: I've heard of the 'pumping' effect that sometimes occurs when a signal is compressed, how can it be avoided?
A: If the release time is too short, the signal level may 'pump', in other words, you can hear the level of the signal going up and down. However, a release time that is too long will result in the level of quiet sounds following a loud beat to be reduced even further. In addition, having the threshold set below the level of the kick drum and the release time set relatively long will punch holes in the track as the level drops with each beat. If the release time is adjusted to be much faster then an entirely different, dynamic-sounding mix can be produced. As a rule, a good starting point for release time lies between 0.2 and 0.6 seconds.

Q: What can the inserts do?
A: Both Inserts are 'split-configurable'. This means that Insert 1 can split the EQ from the signal path if the option is selected and Insert 2 can split the dynamics. Also, Insert 2 is flexible as to signal positioning and defaults to pre-dynamics but can move to post- if desired.

Q: What if I want my dynamics processing to occur pre-EQ?
A: No problem; the EQ and dynamics sections can be switched so that the dynamics processing precedes the EQ section by a single push of the 'Pre-EQ' button on the front panel.

Q: Is there any way to configure the ISA430 MK II as a stereo unit?
A: Yes; although a single ISA430 MK II can act only as a mono or split mono unit, it's possible to link 2 MK IIs together, using the 'dynamic link' socket on the rear panel. Using a single stereo TRS jack cable, this allows stereo operation of the compressor, plus dual mono EQ. You can also use a single ISA430 MK II as a stereo A/D converter, see questions 15.) and 23.) below for a full explanation.

Q: How do I control which ISA430 MK II will be the controller and which will be the slave when using two together for stereo compression?
A: Whichever ISA430 MK II is generating the greater control voltage will be the controller. So, set one of the MK II?s compressors to minimum ratio and maximum threshold, and the other compressor will then always be the 'controller', with any changes made on the controller knobs affecting both channels in the same way.

Q: Does the ISA430 MK II have the same kind of spectacular bandwidth that has given the Red Range its reputation for 'open-ended' sound?
A: Yes. The bandwidth of the ISA430 MK II is 10Hz to 200kHz!

Q: Can I use all the different sections of the ISA430 MK II at once?
A: Yes. If you want to use the mic pre, hi- and lo- pass filters, parametric and shelving EQ, Compressor, Expander/Gate, De-esser, Limiter and digital output all at the same time, as one huge 'super channel' you can. You can also take any section out of the signal path independently with a single button push. Or you could use the ISA430 MK II in 'split mode'.

Q: What is 'split mode'?
A: Split mode allows the ISA430 MK II to act as separate processors at the same time, handling totally separate audio signals. So one channel of audio can be routed through the EQ sections, with a second, discrete audio channel being routed through the dynamics sections. Furthermore, if the mic-pre is also being utilised to output direct to a recording format as well as the ADC dealing with 2 further signals, the unit is acting as four separate processors at once!

Q: Can I route any EQ sections to the dynamics?
A: Yes: the hi- and lo- pass filters, the low-mid and hi-mid parametric EQ, and the hi- and lo- shelving EQ can all be routed independently to the sidechain of the compressor, or to the sidechain of the gate. This means that you can control the action of the compressor the gate from any individual section of EQ, (?frequency selective compression.?) Also, you have a ?listen? button in the Compressor, Gate and De-esser sections, which allows you to monitor whatever is feeding the sidechain of each section so that you can easily hear and tune the frequency you want to trigger each dynamics processor. There's even a separate 'listen' LED by the main meter to warn you that you are listening to something other than the main output- like a 'PFL' warning light on a mixing console. The VU meter can also be selected to view the sidechain for additional control.

Q: Can I use the ISA430 MK II as a 24/192 stereo A/D converter?
A: Yes- the external input, plus the line input (bypass on) or the ADC inputs can be used as a stereo feed to the optional A/D converter. They also pass through the Soft Limiter before reaching the A/D, preventing digital clipping.

Q: What if I want to use the Mic Pre in isolation?
A: There's a 'post Mic Pre' output which allows you to take signal out of the ISA430 MK II from a point immediately after the mic pre. Using the ISA430 MK II in this way provides a very short signal path to tape, for ultra-clean recordings. Also, connecting the 'Post Mic Pre' output does not interrupt the signal flow from mic pre to EQ, dynamics etc, so a direct feed to tape can be achieved whilst simultaneously allowing processing of the same source signal.

Q: The 'Mic air' button sounds great but what's actually happening to my signal?
A: This feature increases the impedance effect of the transformer on high frequencies, adding further 'air' to its sonic quality. It does this by including an inductor circuit into the secondary of the transformer, making the pre-amp have an input impedance that varies with the frequency, having a smaller voltage drop at the top-end. So, additional clarity is introduced by the interaction between the mic and pre-amp alone, without EQ.

Q: What if I experience problems with the gate 'chattering'?
A: The ISA430 MK II is equipped to deal with this- simply pressing the 'hyst' button which introduces hysteresis, solves the problem. (Gates sometimes 'chatter' when the source audio is just above or just below the threshold level, (the gate is constantly trying to open/close/open/close etc) Hysteresis reduces the dB level at which the gate closes from eg -55dB to -65dB. Thus even if a signal is modulating whilst fading out, the gate is prevented from 'chattering.' Since hysteresis is non-destructive in terms of having no other effect on audio, the 'hyst' button should be left on most of the time when using the gate.

Q: What about metering?
A: The Main input meter can display input level, insert return level (very useful for monitoring dynamic input level in split mode), compressor gain change and sidechain level. Additionally, the vertical LED metres can monitor the input and output of the unit or the input to either ADC. The latter inputs occur after the Limiter so can be an indication of its effect. An Audio O/L LED fed from multiple points is also present to indicate when 0dBFS has been reached.

Q: The Limiter is described as 'soft limiting' What does that mean?
A: Derived from the groundbreaking Soft Limiter featured in the ISA 428 Pre Pack, the opto-circuit has different ratios as it approaches peak ?Full Scale? level (0), whereby the ratio becomes infinity. This creates a softer limiting effect but still ensures that the maximum level isn?t exceeded.

Q: How does the De-esser work?
A: The De-esser uses Focusrite?s proprietary phase invert technology. Once the user has selected the frequency at which the de-ess is to occur, the ISA430 MK II generates a 180º out-of-phase signal at that frequency which cancels the specific frequency selected at the moment it occurs, without having a negative effect on other related frequencies.

Q: When I travel internationally can I take my ISA430 MK II with me?
A: No problem. The power supply is a multi-tap design, so all you need to do is turn the fuse holder around to change the voltage to match whichever country you are in.

Q: Is there an optional digital output card?
A: Yes. The card offers a stereo A/D converter, with 24/192 spec. (selectable options from front panel buttons.) The single card fits into the main 430 MK II. The card includes Wordclock and, uniquely in the processing world, a Digidesign ProTools? Superclock direct connection via an additional BNC connector so that the unit can be slaved to an external master clock. It allows 16, 20 or 24-bit operation at 44.1, 48, 88.2, 96, 176.4 and 192kHz sample rates. Digital audio formats supported are SPDIF and ADAT (on optical cable) and AES-EBU/SPDIF on 9-pin. The card can be ordered as part of a ?digital-ready? ISA430 MK II when the main unit is purchased, or can be retro-fitted later. So, if you want to take the output of the ISA 430 MK II to a digital system that doesn't support 24-bit 192kHz, no problem; you can select any of the range of different clocks and bit rates as well as choosing to use an external clock source from the front panel.

Q: Why is a Superclock input important?
A: If a customer has a Pro Tools TDM system and wants to lock it to an external analogue multi-track (s)he needs a USD, (Universal Slave Driver, Digi's premier sync box.) This box looks at the speed of incoming timecode and then varies the Superclock frequency up and down to match. Therefore, because the Superclock is basically 256 x the speed of Wordclock, the playback or record speed of Pro Tools is matched (very accurately) to the machine's speed and any attached Digi. Audio interfaces will also be adjusted.
If the customer now wants to record off the multitrack into Pro Tools via an ISA box, they have a problem if they don?t have a SCLK input because the ISA would be running off its own internal crystal and not looking at the speed information being calculated by the USD. It would be running at precisely 44.1 or 48k with a very high stability, however the analogue deck would be ?wowing and fluttering? all over the show.

Therefore by providing a SCLK input, you can use the USD to clock the ISA module, and therefore lock the ISA up to anything you are locking Pro Tools up to.

Also any TDM Pro Tools equipped with a USD can be switched into Vari-speed mode. Using Pro Tools Session Setup window, a slider allows the overall speed of Pro Tools to be moved up or down. This is achieved by telling the USD to adjust it' internal clock and therefore its Superclock output. This varied SLCK output then feeds any Digi interface as above. So if a customer wants to use an ISA430 MK II, but at the same time vari-speed Pro Tools, they need a SCLK input.

Q: Is there an optional digital input card?
A: No, because all the processing in the ISA430 MK II is entirely analogue- so even if there was a digital input, the digital signal would have to be immediately passed through a D/A converter to allow processing!

Q: Does the card include dithering?
A: Yes, the wordlength of a 24 bit input can truncated down to 20 or 16 bits and then dithered prior to digital output.

Q: Why are the Int. A/D and Ext. A/D inputs fed to the digital output card via the Limiter?
A: The input to the A/D converter must not exceed 0dBfs in order to prevent digital clipping. The Limiter therefore comes after the A/D converter inputs so that the user is protected from digital clipping.

Q: Can I go lock straight to Pro Tools from the digital output of the ISA 430 MK II?
A: Yes, the digital output board is designed so that it can synchronise to external wordclock signals, or to Digidesign's Superclock.

Q: Why is 24-bit 192kHz specification important?
A: An A/D converter works by sampling the audio waveform at regular points in time, and then quantising those values into a binary number, which relates to the number of bits specified. The quantised signal must then be passed through a D/A converter before it becomes audible. In simple terms, the D/A essentially 'joins the dots' plotted by the A/D converter when the signal was first converted to digital. The number of dots to join, combined with how little those dots have been moved, determines how accurate the final signal will be compared to the original. The greater the sample rate and bit rate, the more accurate the whole digital process is. So 24-bit/192 kHz performance will ensure more accurate digital transfer of your audio information compared to the old 16-bit/ 44.1kHz standards. (You can still use these standards for compatibility reasons if you need to as the ISA430 MK II also allows 16-bit/44.1 kHz operation.)

Q: Can I retrofit a digital board to an analogue 430 MK II at a later date?
A: Yes, you can do it yourself- it can easily be retro-fitted by the customer without any soldering etc, just a few screws to undo, and one clip-connector to join to the main PCB.

Q: What are the differences between the ISA 430 MK II and the ISA 430?
A: The MK II has variable mic-pre impedance, as featured on the ISA 428 Pre Pack, allowing the performance of the unit and microphone connected to be tailored to a suitable level and response. The MK II runs up to 192kHz, with 1- and 2-wire modes selectable at the rear plus SPDIF available on optical cable. The MK II has dBFS metering on the right hand side with optional viewing of the ADC inputs, as well as a VU meter with selectable calibration and additional sidechain view. The compressor on the new model has a variable blend, with a dial to adjust the mix, and contains VCA and opto-circuitry. The 'limiter-configurable' nature of the opto means there are a total of three types of compressor. Also, the 'auto release' now has its own dedicated switch and the compressor can be positioned 'post-sum' or ?pre-EQ?. The 'soft limiting' of the MK II can be used on analogue and digital outputs simultaneously. The MK II's shelving includes 2 extra frequencies per band: 20 and 655Hz for LF and 1.5 and 2.2kHz for HF. The mic-pre transformer features an optional inductor circuit for boosting HF and adding 'air' to the signal, and its gain controls are identical to the ISA 428. There are two inserts on the MK II, both being 'split-configurable' with movable routing facilities. Lastly, the MK II's ADC inputs are both XLR and the line input is now routed through the input transformer as with the ISA 220 and 428.

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: 100µs 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

Weight
• 7.58kg
• 16.7Ibs

Dimensions
• 484mm (W) x 85mm (H) x 250mm (D)
• 19" (W) x 3.5" (H) x 9.8" (D)

TEC Award Winner
Mic Pre Technology Category
2004





TEC Award Nominee
Mic Pre Technology Category
2004

Sound On Sound Magazine review quotes
Jan 2004
Hugh Robjohns,

“The ISA 430 MKII boasts impressive connectivity for a single-channel pre-amp."

"Both clean and processed versions of the input signal can be recorded easily to DAW, if required, and I think this is an excellent facility."

"Fortunately, things are mostly logical and intuitive, and the panel is clearly marked and well laid out."

"The mid-band parametrics are as comprehensive as ever, with +/-18dB boost or cut ranges, fully variable Q (bandwidth), and usefully wide and overlapping frequency ranges."

"The shelving section boasts two new frequency positions to make the ISA 430 MKII a little more flexible, but without compromising the fundamental ISA 110 circuit design... these are well chosen and flexible options."

"The compressor section has been updated with two alternative gain control elements... these provide very different sonic characteristics, adding to the colour and character of the unit."

"The Focusrite de-esser is unusual in that it works as a subtractive process, the sibilant signal is detected in a sidechain, and then the unwanted element is subtracted from the main signal so that the latter is affected only at the moment of sibilant reduction, resulting in a more transparent process."

"The last stage of signal processing is the soft limiter... this provides very effective overload protection for the A/D card, as well as clamping the analogue output to +22dBu."

"As with other Focusrite models, the pedigree of this unit is immediately evident in the clear, transparent, open yet full-sounding signal path, the hallmark of a very high quality pre-amp and processor. The addition of switchable input impedances will be appreciated by many, as a useful means to tailor the sound of a microphone without resorting to the equaliser. This facility impressed very much in the ISA 428, and its translation over to the ISA 430 is most welcome. Likewise the mic ‘Air’ facility, which I found extremely useful on almost everything!... I found it particularly useful when close miking instruments, to restore some of the lost brilliance and ‘air’. I can’t think of a better word which is inherent in such an approach."

" The provision of the three separate sections, filters, parametrics and shelves, and the ability to split them and allocate them to the dynamics and sidechains, makes this an extremely flexible unit."

"The compressor was always a key element in the ‘sound’ of the original device... it just became a whole lot better with the addition of the Vintage mode, providing a rich alternative to the VCA sound... To have the option of both here is pure luxury, and this heavenly state of affairs has been made even better with the inclusion of the Blend facility. I’ve always been a big fan of the parallel compression technique, and the arrangement offered here is a joy to use. Although I only had the ISA 430 MKII for a week or so, I found I used this facility a great deal."

"The gate is one of the nicest available, as well as being one of the easiest to use, it really just does the job asked of it without fuss, and operates in a reliable manner, especially with the Hysteresis mode engaged to reduce the possibility of false triggering on slowly decaying sounds. The ability to quickly flip the filters or parametric equaliser into the sidechain to tidy up the control signal is very useful. I am always amazed at how hard the de-esser can be made to work with minimal side effects, and the provision of the sidechain listen facility makes finding the offensive frequencies very straightforward."

"The soft limiter did the same sterling job here as it did on the ISA 428... this optical limiter does a fantastic job of neatly controlling transient peaks without sounding heavy-handed about it. For the red light junkies out there, this is your saviour, and best of all, most people will never know the concept of headroom is completely lost on you!"

"There was never any doubt in my mind (or I suppose anyone else’s) that the ISA 430 MKII was going to be something special. Taking the features of the original unit and adding all the new tweaks and technologies that the Focusrite back-room boys have developed, subsequently has resulted in just about the best possible recipe for a producer channel. This is the kind of device that mere mortals will gladly die for, but only after they have enjoyed using it for a few decades, naturally! Although we are still talking serious professional gear prices, this is a very attractively priced unit in the UK, offering even better value for money than the original, with a stunningly high-quality, comprehensive and extraordinarily flexible package."

"The ISA 430 MKII has been designed to provide the most complete and superb-sounding channel path available, and it does that in spades... I should think a similar volume will be sold to home and project studios that need just one really good front-end unit, and with the optional A/D card, the ISA 430 MKII has to be one of the best and most versatile units on the market today. I can’t think of anything negative to say about the ISA 430 MKII, it really is that impressive. Committed recording engineers now have a new British standard-bearer when it comes to high-end analogue recording channels."

Pro Audio Review Magazine review quotes
March 2004
Russ Long

"Holding true to the original Focusrite vision, the Class A Focusrite ISA 430 MKII offers an unequalled, uncompromising recording channel that includes a mic/line preamp, equaliser, compressor, expander/gate, de-esser and limiter."

"Several new features significantly improve the performance of the $2,995 MKII over the now discontinued ISA 430."

"I found that the ISA 430 MKII works extremely well with drums and percussion. I had nice results using the box along with an AKG D112 on kick drum with a Shure SM-57 and a BLUE Ball on snare. I also had good results using the box along with a BLUE Bluebird to record percussion."

"I had fantastic results using the ISA 430 MKII to record vocals. I used the unit with the Sony C-800G, the BLUE Cactus and Bluebird and the Brauner VM-1KHE, and every instance had pleasing results. I found that the vintage compressor mode worked extremely well with vocals, especially when using a tube microphone. Plus, the de-esser worked substantially better than my old faithful dbx 902."

"I found that the Blend feature worked extremely well on bass guitar and vocals. This allowed me to create a more compressed track that actually had the feeling of being less compressed."

"I had good results recording bass guitar through the instrument input. The instrument had a nice bottom end but still maintained its presence and definition. I also had good results using a Royer R-122 to record electric guitar and an AKG C28 to record acoustic guitar."

"The ISA 430 MKII’s A/D converter sounds fantastic. At 96kHz, they are every bit as good as anything I’ve encountered. I used the box during a mix to simultaneously EQ a vocal whilst compressing a bass guitar. Though it can be a bit confusing, the complex signal flexibility is one of the box’s strengths."

"In the Focusrite tradition, the ISA 430 MKII sounds wonderful. The box has tremendous clarity and detail and is extremely clean and quiet. The EQ is both musical and powerful and the compressor and de-esser are quick and easy to use, and they sound extraordinary."

Audio Media Magazine review quotes
February 2004
Len Davies

"It never ceases to amaze me how designers always seem to improve on the original. The Focusrite 430 is an amazing unit that’s been praised all over, and is in use constantly, so how could the designers even begin to improve on something that good? From the moment I was informed of the existence of the ISA 430 MKII, I waited with baited breath for the review model to arrive, and the opportunity to find out for myself."

"The connections on the rear panel have been well thought out to be multi-purpose depending on the use. The clever idea here is that when not employed as inserts, Send 1 is the EQ output in split mode while the return is the input to the EQ section, and likewise Send 2 is the dynamics output in dyn split mode while the return is the input to the dynamics section."

"This is not just a case of adding a few extras, the internal layout has been seriously redesigned. The input stage has been expanded to include the same variable impedance as the ISA 428 Pre Pack, but also now includes an Air feature which activates a parallel inductor circuit into the secondary of the transformer... thereby creating a brighter and more spacious sound without the need for EQ."

"The ADC has the same specifications as that used in the ISA 428 and copes with sample rates up to 192kHz, and finally the ISA 430 MKII remembers its settings in the event of an improper power shutdown. How cool is that!"

"The true magic of the unit is its flexibility, as it’s not intended to be just a fixed channel on its own."

"I’ve deliberately not included an ‘In Use’ section as there’s basically no need. It sounds fabulous on everything, although I must add that I particularly love the vintage compression on Drums and Vocals."

"I’m openly biased towards Focusrite products as I absolutely love the thought that goes behind the design, as well as the feel of the controls and the fact that before I unpack it from the box, I know that it’s going to be quality and will always deliver over and above what I’m going to ask from it. Owners of the ISA 430 and 220 will know what I’m talking about, and I’m sure that the ISA 430 MKII will find homes around the world with both new and established facilities and private studios."

"I’m planning a new facility abroad, as part of a current project based around a totally digital studio, and have already suggested a hefty rack of these units for the recording stage. I can’t wait to put a complete drum kit through my own equivalent of the Focusrite console."

Resolution Magazine review quotes
April 2004
George Shilling

"The compressor section has now been enhanced with an alternative to the Class A VCA design in the form of two optical 'Vintage' modes; Compressor and Limiter. I really like the sound of these new settings. They can be really lovely and warm and fuzzy, and the release times are surprisingly fast."

"It all sounds fabulous as expected. The button pushes click nicely, often produce a satisfying relay click, and all statuses are clearly displayed with LEDs."

"The new Producer Pack is the ultimate blue-range Focusrite, with nothing missing. The new compressor modes sound great and the blend control is a very useful feature. The mic pre-amp enhancements present subtle but useful choices... if you like the Focusrite sound and really want all the possibilities presented here, this box has everything, and now even cheaper than the original."