The ISA828 eight-channel microphone preamplifier provides eight original ISA transformer-based preamps in a single robust 2U chassis, offering the Focusrite signature sound at its lowest cost per channel to date.
The eight ISA-series transformer-based microphone preamps feature the same classic microphone preamplifier design as the original ISA110 module from Focusrite's critically acclaimed Forté console (including the original Lundahl L1538 transformer and bespoke zobel network).
The preamps are complemented by eight line inputs, eight line outputs and an optional eight channel 192kHz A-D converter boasting a dynamic range of 122dB. Thanks to its convenient 25 pin D-Type connectors, the ISA828 also integrates quickly and seamlessly with ProTools HD, as well as other popular hard disc recorders and mixing desks.
The microphone input stage additionally includes a variable impedance circuit, allowing the user to switch between four carefully selected input impedance settings. The original ISA110 setting is supplemented by three further impedance settings to either perfectly match the preamp with any microphone, thus maximising level, or to use different settings creatively to shape the sound of the microphone being used.
The four front panel instrument inputs also feature high and low impedance options to provide a comprehensive and accessible DI solution. Insert switches are also featured on every channel, should the need arise to place extra processing between the preamp and converter. Vintage design 75 Hz / 18dB per octave high pass filters are also provided on every channel, ensuring unwanted low frequencies are effectively eliminated.
Finally, every channel features a six LED input meter, complete with global precise meter trim. Metering has been designed to utilise the same reference points as Digidesign’s Pro Tools HD™ system and provides clear and accurate input metering, independent of the DAW.
Rafa Sardina Chooses ISA Range
Rafa Sardina is a Los Angeles-based musician, mixer, engineer and producer with a stellar client roster. Stevie Wonder, Beyoncé and Lady Gaga adorn his credits list, while his foothold in the Latin music market has seen him work with Luis Miguel, Rodrigo y Gabriela, Paco de Lucía and Alejandro Sanz. Rafa has been nominated for an impressive 25 GRAMMY awards, winning 11. His diverse work covers everything from pop to R&B, to classical recordings and movie soundtracks.
His studio After Hours features a wealth of Focusrite gear. Among his collection is a rack of eight classic ISA110 modules from a Focusrite Studio console: considered by many as the finest recording mixers in existence. "My first encounters with Focusrite were with the Studio console at Ocean Way,” Rafa comments. “I had quite a lot of experience in working on that board, and I was very fortunate to work in other studios that had them."
When Rafa left Ocean Way, he continued to be a fan of Focusrite. As he started putting together his own studio, Focusrite gear was top of his list, "I started acquiring quite a few Focusrite pieces like the ISA110s and ISA215s. The ISA preamp sounds great on anything that has high transients, and I love the Focusrite EQ; it is so efficient. It's the kind of EQ that you can actually hear what it's doing well. More recently, I got the ISA 828 and it has become one of my main pieces of gear, not only in the studio but when I travel."
He explains why: "One of the most amazing things about the ISA828 is that you can have up to 20 things connected simultaneously. For a session, it's like a chameleon, you can switch depending on what you're overdubbing, if you're doing some keyboards, or recording a bass track, or just recording some microphones, you can switch between different settings and mark your mic levels so you can easily recall them, all with a single 2U box. Another amazing feature of the box is the impedance selection, which gives you a broad style of sounds, depending on how it matches to specific microphones. When you change the impedance, you can hear how the preamp is matching to the microphone. It can really open the sound up, or it can even make a microphone sound duller than it really is. And maybe that's what you're looking for."
First and foremost for Rafa, "the integrity of sound is the most important element in the studio, no matter what you are doing. You want things to be top-notch quality, you want them to stay the way you envisaged them sounding when you were tracking them."
The Focusrite sound has been at the heart of Rafa's GRAMMY-winning career from the start, and it remains so. "I have compared the old and the new ISA gear, and it really retains that warmth, grittiness, I don't know, the sound that really appealed to me from the very beginning. And that was the main reason why I got the ISA828. The sound comes first; the convenience is very important too, and it is a plus in this box, but the sound comes first and that's the main reason I got it."
We always quote 'real world' performance figures (measured to the AES17 standard). Some companies choose to quote chipset performance, which is misleading.
Mic Input Response
Gain range: 0dB to 60dB in 10dB steps
Input Impedance, variable: 600?, 1k4?, 2k4?, 6k8?
EIN (equivalent input noise): -126dB measured at 60dB of gain with 150 Ohm terminating impedance and 22Hz/22kHz bandpass filter
Noise at main output with gain at unity (0dB): -97dBu measured with a 22Hz/22kHz bandpass filter
Signal to noise ratio relative to max headroom (9dBu): 106dB
THD at medium gain (30dB): 0.0008% measured with a 1kHz -20dBu input signal and with a 22Hz/22kHz bandpass filter
Frequency response at minimum gain (0dB): -0.5dB down at 10Hz and –3dB down at 110kHz
Frequency response at maximum gain (60dB): –3dB down at 16Hz and –3dB down 85kHz
CMRR: 91.8dB (Channel 1, 1kHz, maxiumum gain)
Crosstalk Channel to Channel: with 10dB@1kHz input to chA, chB output =102dBrA. With 10dB@10kHz input to chA, chB output = 84dBrA
Line Input Response
Gain range: -20dB to +10dB in 10dB steps
Input Impedance: 10k? from 10Hz to 200kHz
Noise at main output with gain at unity (0dB): -96dBu measured with a 22Hz/22kHz bandpass filter
Signal to noise ratio relative to max headroom (24dBu): 120dB
Signal to noise ratio relative to 0dBFS(+22dBu): 118dB
THD at unity gain (0dB): 0.001% measured with a 0dBu input signal and with a 22Hz/22kHz bandpass filter
Frequency Response at unity gain (0dB): 0.3dB down at 10Hz and –3dB down at 122kHz
Instrument Input Response
Gain range: 10dB to 40dB continuously variable
Input Impedance: 1M? or 300k?
Noise at minimum gain (+10dB): -90dBu measured with a 22Hz/22kHz bandpass filter
Noise at maximum gain (+40dB): -62dBu measured with a 22Hz/22kHz bandpass filter
THD at minimum gain (+10dB): 0.002% measured with a 10dBu input signal and with a 22Hz/22kHz bandpass filter
Frequency Response at 10dB gain with -10dB input: 10Hz-200kHz +/- 0.6dB
Frequency Response at 40dB gain with -40dB input: -2.5dB down at 10Hz and 0dB at 200kHz
High Pass Filter
Roll off: 18dB per octave 3 pole filter
Fixed Frequency 75Hz measured at the 3dB down point
484mm (W) x 85mm (H) x 305mm (D) (350mm depth with heat sink)
19" (W) x 3.5" (H) x 12" (D) (13.8" depth with heat sink)