The + means improved converters and mic preamps, along with the original Focusrite Studio Console sound
And we quote:
Focusrite (booth 201A) has expanded the Clarett+ range of premium-quality USB audio interfaces for PC and Mac with the introduction of the Clarett+ OctoPre, which builds on the strengths of the popular Focusrite Clarett OctoPre, offering improved converters and powerful professional-quality mic preamps.
The Clarett+ OctoPre adds eight high-quality mic preamps or line-ins/outs to any ADAT-equipped recording interface and offers a huge upgrade to the AD/DA converter chips compared to the previous OctoPre. This means a higher dynamic range, an ultra-low noise floor, ultra-low distortion, and overall some of the clearest recording quality on the market, even compared to competitors’ products costing three or four times the price per channel. One way that Focusrite has achieved this is by focusing on the components that affect recording quality the most: the converter chips and microphone preamps.
Because the conversion is so pristine, the Clarett+ OctoPre is a perfect choice for the engineer who wants to go into and out of their DAW to track or mix with outboard gear while maintaining the highest audio quality. Eight flexible channel inserts let users track through their favourite outboard components and capture that gear’s true character. Connecting Clarett+ OctoPre to a Clarett+ 8Pre via ADAT provides 16 channels for recording.Clarett+ OctoPre is also a great choice for tracking drums, mixing livestreaming performances, connecting to analog synthesizers, or just upgrading a desktop interface with more I/O. Additionally, premium, all-analogue circuitry with relay control emulates the extremely transparent ISA 110 mic preamp from the classic Focusrite Studio Console with an Air mode that switches the input impedance and adds two cumulative high shelves for up to a 4dB boost in the high frequencies to add clarity and presence that makes vocals, drums and acoustic instruments shine.
The Clarett+ OctoPre also includes Focusrite’s Hitmaker Expansion Bundle, a package of plug-ins valued at $1,300. Users can create studio quality vocals, powerful guitars, luscious keys and huge drums, then mix and master with iconic Focusrite studio hardware – all in the box with the Clarett+ OctoPre. The bundle lets users capture inspiration with creative tools including the Softube Marshall® Silver Jubilee 2555, Antares Auto-Tune® Access, Brainworx bx_oberhausen and XLN Addictive Keys and Addictive Drums 2: Studio Rock Kit. Mixing and mastering are enhanced with classic studio tools like Relab LX480 Essentials, Focusrite Red 2 & 3 Plug-in Suite and the Brainworx bx_console Focusrite SC and bx_masterdesk plug-ins. Additionally, the Focusrite Plug-in Collective allows users to get a new plug-in and exclusive offers from a new partner every few months.