Boss ME-80 to T1®
The Boss ME-80 is a guitar multi-effects unit for electric guitar. The outputs are designed to be connected to an electric guitar amp. These outputs will not sound their best when connected to a full range system like your L1® connected to your T1 ToneMatch Audio Engine. For best results, you will want to activate the guitar amp simulators in the Boss ME-80.
Referring to page three of the Boss ME-80 Users Guide. Boss ME 80 Users Guide
To activate the amp simulators you need to connect something to the Record Out / Phones Jack.
T1 ToneMatch Audio Engine
You can plug an empty jack plug to the Boss ME 80 Record Out / Phones Jack. This turns on the guitar amp simulators. Then you can connect Left (MONO) output to L1 Compact Channel 2. Set the ToneMatch switch to Line Level.
Try this Preset to start and then take a spin through the others in case you find something that suits you better.
Please see the live discussion: multi effects