In Dev Review: Focusrite ISA-ONE Single Channel Mic Preamp

The Focusrite ISA One

I’m not entirely sure what there is to say about the ISA preamp that hasn’t already been said.  It’s a legend.  The original Focusrite Forte console of the 1980s that first introduced the technology was a game changer, and the modern-day ISA series remains largely unchanged from the original.  I’ve used ISA preamps on more sources for more recordings than I count.  If I’m doing a high-budget professional project, I want a combination of Daking and ISA pres on the drum buss.  Period.  Nothing else ever sounds as good to me.  Pound for pound, as far as I’m concerned, the ISA is the platonic workhorse preamp.  With all due respect to Focusrite’s now defunct Red series, I think the ISA is the better pre at half the price.  It makes perfect sense to me that, through the last quarter-century, no matter what else has changed, Focusrite has left their ISA preamps damn well enough alone.  Were I restricted to the use of a single type of preamp for the rest of my recording career, the ISA would make my short list of candidates.

Of course, these are boutique pres, and they carry a boutique sticker.  The 8 channel ISA 828, which is a fixture of major studios, is a $3000 unit.  Most of us are lucky to be able to budget that kind of money for our entire home studio.  There’s a reason why companies like Focusrite and Blue, who built their reputation on stratospherically expensive boutique pieces, expanded to and eventually focused the bulk of their marketing efforts on much cheaper lines.  You will not find yourself selling all that many $6000 microphones, but you will certainly find yourself selling a lot of $200 ones.  To be fair, some of the cheaper gear is still pretty good.  Focusrite’s own Saffire pres, for example, are eminently decent.  They’re clean, they have enough gain, they’re relatively detailed; they work.  Their price necessitates design compromises, and for the most part the right compromises have been made.  For most home studios they’re perfectly adequate.  But what if some of you uppity mortals decide you want a little taste of the good stuff?  Obviously you can’t afford eight of them, but what if you wanted just one ISA pre for lead vocals and the like?  Well my friends, may I turn your attention to the Focusrite ISA One.  Every laudatory statement I’ve made about any of the onboard preamps in any of the excellent interfaces I’ve reviewed (with the possible exception of the RME Babyface) you can pretty much shelve for the time being.  Because you’re about to get a crash course in the real elite.

Sound Quality

The ISA One is exactly what it sounds like: a single channel ISA pre, with an independent DI.    Focusrite also makes a version with an onboard ADC card, and while my review unit does not include it, my understanding is that it features the same converters you can purchase for the 428 and 828 series, in which case I can assure you the converters are excellent.  The DI, however, I can directly attest is top notch (my upcoming professional release actually features the ISA DI on electric bass).  Some may find it a touch harsh for a softer, jazz guitar type sound, but for grungier rock guitars and bass of any kind, it has a fat, growly bite that will send shivers down your spine.  It also has a surprisingly good onboard headphone amplifier (it’s as good or better than many of the entry-level to mid-range dedicated HPAs I’ve heard), which will give you latency free monitoring of the active inputs as well as playback of a line-level stereo signal through dedicated balanced back-panel inputs.  Gross gain is attenuated via a 4 step detented pot, and trim can be adjusted within a 20db range from there.  The sheer amount of available gain is monumental, so start out gingerly.  That said, with a picky ribbon, don’t be afraid to crank it up.  All that nasty noise you’d pick up from a cheaper pre simply will not be there, no matter how hard you drive it.

I’ve worked with ISA preamps in some incarnation or another for the better part of a decade now, so I have a fair bit of experience with how they react in a wide range of situations.  The short version is that they always work, and they usually work beautifully.  ISA pres don’t have quite the same crystalline transparency as some of the more renownedly neutral boutique pres, such as the Grace Design M201 or Benchmark MPA-1, and they sound positively fat next to the likes of a ‘straight wire with gain’ pre like the DACS Clarity or Earthworks ZDT 1024.  That said, they don’t have anything close to the kind of brashness or coloring of the classic ‘preamps of character’, such as the Neve 1073 or A-Designs Pacifica.  What they do have is unbelievably wide frequency extension which in turn gives it a very natural, organic voicing and excellent detail retrieval, and a touch of warm grain that you can either accentuate or minimize by changing the input impedance setting.  Different microphones will react differently to a given impedance setting (ribbons, for example, tend to prefer a higher input impedance), but as a general principle, go for the low-z or ISA 110 settings for a cleaner sound, and the mid-high z setting for an edgier one.  The differences are subtle though; regardless you will end up with a quite breathtaking, sweeping, open sound with tight, controlled lows and delicate, airy highs.  If you’ve never used a boutique preamp before, the ISA One is an ideal place to start.  You may find yourself wanting a more aggressive color for certain situations, and there is a camp that would argue that the ideal preamp essentially disappears, but for my money, ISA preamps are about as close to perfect everyday pres as you can find.

Design and Build Quality/Ease of Use

The ISA One is a stunningly good looking piece of gear.  The build quality is absolutely top notch: from the heft and feel of the unit in your hand to the hole-punched double ‘F’ venting on the sides, to the fit and finish on the indicators and pots, everything about the ISA One is done right.  The design is gorgeous; the all-metal casing and leather strap, the classic blue and yellow color scheme and old-school indicators and the awesome retro analog VU meter all give the ISA One an aura of days gone by.  It feels like a vintage piece in every sense, and that’s a huge compliment.  The ISA One is the exception that proves the rule that they don’t make ‘em like they used to.  It feels like it will last for decades, and given that the preamp topology hasn’t changed much in the last quarter century, odds are you’ll find yourself still wanting to use it right down to its dying breath.

If you’re accustomed to working with unnecessarily convoluted software control systems and sub-menus, the pure analog immediacy of the ISA One will likely be a refreshing departure.  It seems like psychosomatics, but for whatever reason, you will never experience quite the same kind of connection and control with a mouse and a computer screen that you will with physical buttons and knobs.  The ISA One is a very simple unit, and using it is utterly intuitive.  Just plug in your mic, rout the output to your converters, set your gain and impedance/phantom power settings and you’re good to go.  Straight out the box the ISA One has a very shallow learning curve, and if you have any experience with any kind of mic pres at all, you’ll have no trouble using any and all of its features.  Every input and every control is so thoughtfully laid out and precisely labeled that within minutes you’ll feel like you’ve had the unit for years.


I’m combining the two for the purposes of this review, because as far as I see it, price is going to be the primary factor that limits ISA One’s usefulness.  In terms of the versatility of the ISA One as complete unit, my only qualm is with the fact that it’s single channel.  There are enough instruments that I like to mic in stereo that only having one pre to work with limits the number of sources I can comfortably run through it.  That said, in terms of that pre alone, and what it can lend itself well to, if you didn’t gather by now, it’s probably the most well-rounded preamp I can think of.  It does have something of a more vintage sound on account of the slight bit of grain you’ll always end up with, but you can always count on an ISA preamp to deliver for you.  Precious few mics are too picky for an ISA pre to push.

At $500, however, the ISA One is essentially in a class of its own.  The only other single channel mic pres I can think of at that price are the True Systems P-Solo and the Grace Designs m101, both of which (but especially the latter) offer up some stiff competition.  And this presents two significant issues.  First, there are a LOT of good two channel preamps at that price range, and many situations simply necessitate a stereo micing setup.  Now, pure sound quality-wise, the ISA One is better than pretty much all of them, but at twice the price per-channel it should be.  Secondly, and more importantly, to justify this level of fidelity, you really need Apogee Duet grade converters or better, and at that point, from a price perspective, you could just as easily buy a unit like the RME Babyface that sports excellent onboard preamps (albeit still not in the same league as the ISA One, especially from a clean gain perspective) and freakishly nice conversion for a solid $250 less   Basically, my point is that the ISA One feels sort of like a ‘tweener.  From a studio perspective, I fear that for those who are looking to put together something small and low-budget, $500 for a single pre is just too much, and for those who are trying to build out a more professional-grade project studio, a unit like the ISA 428 or 828 is going to be more practical.

There are, however, two distinct niches where I see the ISA One as ideal.  The first is for singers, voiceover talents and solo instrument overdubs.  If all you need is a single, very high quality preamp, the ISA One will give you a level of fidelity that you’d be hard-pressed to match at its price.  For those who are a fan of ribbons as well, this is probably the only $500 preamp on earth that will give you enough headroom for quiet sources.  And given the quality of the independent DI, singer/songwriters could comfortably cut whole albums using an ISA one plus converter of choice alone.  The second is as a portable super-channel.  Especially if you buy it with the built in ADC, you could theoretically pair it with a unit like the RME Babyface that has ADAT in, and expand your ability to do quality overdubs or live micing exponentially.  You could run a set of overheads off the onboard pres and use the ISA One to power a single omni or figure-of-eight microphone for a more holographic sound, or to push a spot mic on a picky solo instrument like voice or trumpet.  You could get a quality drum sound using the ISA One to push a nice ribbon in front of the kit to pick up the toms and the kick, and use the onboards to power overheads.  I even know a couple of cats who use it as a super channel for live gigs.  Being able to pack it up and go is a major upside.

The Final Verdict

The Focusrite ISA One is an undeniably sexy piece of equipment, and a stunningly good sounding one at that.  The only question is going to be whether or not it fits your budget and needs.  If you find yourself in need of a single channel, truly boutique grade mic pre you can use with essentially any mic and on any instrument, and the ISA One can fit into your budget, I strongly recommend giving it a shot.  For the purposes of cutting demos and the like it’s probably a bit overkill; for the money it costs you might be better off just getting a really high-end all-in-one like the RME Babyface.  But if you want to be able to cut genuinely professional overdubs or voiceovers, or just have a single, portable super channel you can take anywhere to push your most important source, the ISA One is a real facilitator.  Make no mistake, this is multi-million dollar studio grade gear.  Think of it as the cheapest cure you’ll ever find for upgraditis.

Focusrite ISA One Review by ProAudioStar

Dev is a professional jazz-fusion composer, singer, sound engineer and front man for the band Wire Spoke Wheels, living and operating in beautiful Bushwick, Brooklyn. He’s also co-founder and co-chairman of Frost Audio, a small Michigan based audio company specializing in high performance cables and loudspeakers, all hand-made in the USA. He’ll be releasing his next studio album, Tears of Men, in early 2011. To learn more or hear his work, check out

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About Dev

Dev is a professional jazz-fusion composer, singer, sound engineer and front man for the band Wire Spoke Wheels, living and operating in beautiful Bushwick, Brooklyn. He’s also co-founder and co-chairman of Frost Audio, a small Michigan based audio company specializing in high performance cables and loudspeakers, all hand-made in the USA. He’ll be releasing his next studio album, Tears of Men, in early 2011. To learn more or hear his work, check out

6 thoughts on “In Dev Review: Focusrite ISA-ONE Single Channel Mic Preamp

  1. Great review with enough details to convince me to grab one.

    Should provide a nice complement/opposite to my British Joe Meek VC3v2.


  2. Very interested in this pre, Ive just heard so much about the Golden Age Pre that Im alittle indecisive

  3. The Golden Age Pre73 is a TOTALLY different beast color-wise from this. That’s a Neve 1073 clone; there are dozens of them out there, the Golden Age making it’s name via being more or less the least expensive, while still getting the job done. It’s a much more colored sound than the ISA series. If you want fat, rich, gooey, tubey goodness, the Pre73 is a really great choice at that price range. If you want something more even-keel and versatile, the ISA is the better bet. They’re both very good pres, but consider this; in my professional studio, I have an ISA 828 unit that I use for drum buss and a wide variety of acoustic instruments, but at the end of the day it was worth the money to me to upgrade to a Vintech 1073 clone over the Golden Age one. If you want that 1073 color, and the Pre73 is what’s in your budget, don’t look back – it’s a great little unit. But pound for pound, even though we’re comparing apples and oranges here, I think the ISA pres are better.

  4. I bought this pre amp and it works great. Looking for a new interface I found the duet 2 and heard it has a good pre amp on it as well. Do you think I had the duet 2 I wouldn’t need the isa one? I’m trying to power up my shure sm7b

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