Focusrite A/D converter cards are designed to meet the absolute maximum design specifications possible for the converter chip-sets used. However the real benefit comes from using a recording system in which the ADC is included within the closed environment of a single box. The integral closed environment allows a shorter record path to digital, with no unnecessary analogue connections out of the Focusrite box to the input of the recording equipment.

With the addition of the stereo A/D card the ISA 220 and 430 can be used as high quality mono/stereo tracking converters or at mix down as a stereo converter channel for routing complete mixes to digital media.

At the heart of the stereo A/D card is a high quality 24-bit 96 kHz Delta Sigma converter running at 128x oversampling for maximum conversion performance. Focusrite proprietary designs are used for all internal clocking and phase lock loop circuits to guarantee the absolute minimum jitter possible, whether free-running or locked to wordclock or Pro Tools Superclock.

When recording to non-24-bit destinations, 16- and 20- bit dithering can be selected to ensure the highest quality digital conversion for any format. The ISA's optional A/Ds are stereo and allow for input from internal (post-processing) and external sources simultaneously giving a clean, protected, high-quality path to stereo digital media.

The internal input to the A/D is normally fed from the internal channel signal passing through the EQ and dynamics. However, this path can be broken by a signal connected to the rear INT A/D Direct jack, which allows a signal to be directly connected to the A/D input (replacing the internal processed signal).

An additional external input (XLR on the rear panel) gives the user access to the second channel of conversion on the A/D card for stereo recording with two units or for an additional external source.

This a multi-format card – ADAT output is included; for AES/EBU or S/PDIF output, optional cable assemblies are required (see "Accessories & Options" at upper right).