Focusrite ISA 428
Focusrite ISA 428

ISA 428, Solid-State Pre-amp from Focusrite in the ISA series.

All user reviews for the Focusrite ISA 428

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Average Score:4.3( 4.3/5 based on 6 reviews )
 2 reviews33 %
 4 reviews67 %
Value For Money : Excellent
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moosers's review

Focusrite ISA 428
The Focusrite ISA 428 is a four channel set of mic preamps. These are solid state preamps where each channel has XLR and 1/4" inputs and outputs. There are also 1/4" inputs on the front of the box for each of the channels if you want to go direct. It is rack mountable and will take up two spaces in your rack case.


The make up of the Focusrite ISA 428 does take a second look as it's got the full spectrum of parameters for each of the channels. Each has built in phantom power, phase flip, mic/line/instrument input selector, and impedance. To set your input gain, you've got a fixed line input parameter as well as a separate knob for making finer adjustments. It also has a button that changes the range of the input gain, as well as a built in filter. I've never had a look at the manual.


The sound of the Focusrite ISA 428 is pretty clean and transparent. It reminds me somewhat of an API, but doesn't sound as pristine to me. While these are respectable preamps, personally I prefer the Neve sound when compared to something more transparent like this or and API. Of course it depends on what you're recording, and these can be great for a variety of applications. They're perfect for a smaller or home studio owner who wants a set of cheap preamps that will certainly sound better than your audio interface's stock pres.


While the Focusrite ISA 428 preamps are pretty good sounding and will do a nice job of capturing your microphone's sound, I do think it's a bit steep for the price. While you do get four good preamps, I'd probably put the money into something like a 500 series where I could get better preamps and expand upon it. This said, it's not a bad overall deal at all and I can see how many would be attracted to it. I'd say yes for the home studio owner, but no for the pro.

soccerplayer25's review

Focusrite ISA 428
The Focusrite ISA 428 is a solid-state analog external preamplifier. There are both XLR and 1/4'' inputs and outputs and has inserts for instruments on the front of it. It is a rackable unit.


While one might get lost looking at all of the knobs at first glance, its a pretty easy unit to get used to with a ton of control. It has both a fixed gain knob which you can move to certain fixed levels and a free one to adjust smaller increments for total control. I've never had access to a manual for it.


While it certainly doesn't have the warmth that a tube preamp would have, it does have a very clear sound and sounds great both with mics and directly plugged in. It doesn't color the sound too much, depending of course if you use the filters or some of the other features. If you go straight through with the preamp it will give you quite an accurate sound.


I've been using this for about 6 months and the thing I love most about it how many different options you have to shape your sound. Its also great to have 4 separate preamps at a very reasonable price when you break it down to price per preamp. It is a great all in one solution if you need a few extra high quality preamps. However, if you are looking for a top end preamp, I would look elsewhere for a single or dual channel preamp that will run you around the same price, but the preamps will be higher quality.

ouindel's review (This content has been automatically translated from French)" transparent"

Focusrite ISA 428
analog transistor preamp, XJR and Jack, rackable


Simplicime, I never read the manual, you must increase the volume increments for the settings and then end, we need another knob, and must be used ss'y apès it rolls ... impedance settings and the source (line, mic, instrument) and then cut down a knob


RAS is the best preamp I


02 years since, unwanted, it's a bit expensive but what fun ....

Fabsalab's review (This content has been automatically translated from French)" This is happening everywhere"

Focusrite ISA 428
A transistor analog
Xlr and jack
Optional digital card
It is rack mountable


Very simple configuration
Manual clear


The sound is good, different impedances are effective and can have quite different sounds.
The transparency of which has a little crush but boosts


How long you use it?
5 years
What is so special that you love the most, least?
the choice of different input impedances

How would you rate the quality / price?
good, but it's MKI version that I use and recommend the MKII version produced under other conditions than the original ... By testing means different things between the MKi and MKII ...
After if you do not use it at the same time I'm not sure we can do the différenec between version I and II
With experience, you do again this choice? yes, but with the digital map again!

jfherts's review (This content has been automatically translated from French)

Focusrite ISA 428
4 preamp transistor
see manufacturer ...


Nothing too complicated ...

You turn the knobs to the level, the indications are clear on the frame (high pass, impedance), the VU meters comprehensive (VU meter + meter peak on the right = very useful)


If you calculate the price per channel, one has for his money. We feel that the unit is well designed (gain in 10 dB + trim), the high pass is very high! and it is awesome ... very useful for cleaning taken upon registration. The ability to change the input impedance gives it a more versatile (softer sound when the impedance is low and more nervous when the impedance is higher)

Having already worked with many preamps (Chandler, API, Great River, Millennia, amek ...), we can say that this happens to give a Focusrite sound recording professional. It is clearly above preamps typed "home studio", but has not the finesse of the great high-end preamps (chandler, great river ... which are more than 2000 € per pair).

The sound is rather straight, nervous, a little dry (but that's what I was looking at first), well enough cash preamp sends fairly level.


Good compromise, its not too expensive to pro ... But do not fall into the category of very high quality. API, Great River's really over, but the budget is not the same. And the higher up the budgets, the more you end up with a preamp with more character. This is fairly neutral. He gives a dry, firm and thus is quite versatile. I sell all my old preamps "middle range" because Focusrite takes over every time (at equilibrium frequency, dynamic, fishing ...)
No regrets ...

Rainqlm's review (This content has been automatically translated from French)

Focusrite ISA 428
4 channels Preamp Focusrite ISA serial card option 8 A / D converter

While specific level and connectivity, this device deserves a 11/10!
Mic XLR + Jack + Line jack on the front instrument - XLR - insert - all on 4-way
4 XLR inputs to attack the lanes 5-8 of the A / D

In fact it is expected to have two ISA 428 and one card A / D, for example ....

Full side adjustment is hyper:
- Choice of mic / line / instrument
- 48v
- Adjustment of the impedance (4 different, interesting for ribbon microphones for example)
- Low-cut filter with adjustable frequency .... 30 to 240 Hz I think (sic)
- Phase inversion
- Separate volume and gain (gain range from 0 db A60!)
- VU meter nice
- 8 LED meters for the converter
- Setting the frequency from 44.1 to 192 kHz
- Function "soft limit"

In short nothing is missing!


Everything is clear, well lit, buttons and other buttons portards are very nice and precise, and more beautiful it is!


So the sound, I put 9 / 10 when compared to a preamp tube to € 2000 and a converter apogee upscale .....
that's if there's nothing to say is very right on the other hand, do not look for the color or the large and clear, have to take a tube or a tech Summit for!
But the sound is present, right, very well-defined medium, a good dynamic.
Side converter is in the range of Digidesign MOTU 192HD or (as I think it's the same ship), so good, just below an apogee.


I love this device, a little lonely in his world eventually, but I think it's really well thought out.
It is very comprehensive, there's everything you need, and finally with 428 and 2 ISA card A / D was a set 8 preamp / converter of high quality for € 4000.