FOCUSRITE ISA 428 MkII

The Focusrite ISA 428 MKII is a versatile and flexible four-channel microphone preamplifier in a 2U rack-mount design equipped with Lundahl input transformers and independent line and instrument inputs. The preamp topology is based on the circuitry of the original ISA110 designed by Rupert Neve, a circuitry that has been used for decades in Focusrite's most successful products.

The Lundahl LL1538 input transformer used in the original RED modules lends a special character to the sound that cannot be replicated in any other way. Another distinctive feature that will affect the sound of the connected microphone is the ability to select one of four carefully preset impedances (Low / ISA 110 / Med / High). This choice really does significantly affect the input sound, and you can experiment and bring out the character of the microphone or, conversely, opt for a completely transparent presentation, it's up to you. Within each channel, the preamplifier offers independent adjustment of all the important functions, starting with the impedance selection and precise gain adjustment via two potentiometers and a range knob, this combination makes the input gain as high as 80 dB. You'll also find switches for phantom power, phase rotation, insertion channels into the signal path (8 x Jack 6.3 mm SEND/RETURN) and last but not least, an HP filter with a continuously adjustable range of 16 - 420 Hz and a steepness of 18 dB/octave.

In addition to the main microphone (4 x XLR) and line (4 x Jack 6.3 mm TRS) inputs on the rear panel, instrument inputs (Jack 6.3 mm) are available on the front panel, so you can use the preamp's potential to enrich the sound of your instruments. The last A-D input jacks (4 x XLR) are for connecting line signals and can be used when you purchase an optional 8-channel A/D card (ISA ADN8).