I have a Helix LT...delighted with it. Occasionally, I need to run an Acoustic guitar with Vocals...as there's no MIC Input on the LT, decided to try a MIC to LINE Adapter. I got this one -
https://www.gear4music.com/…/Audix-T50K-Impedance-Matc…/ST8…
It works great ! I can plug my Dynamic Mic in via the RETURN 1 Input on the LT, made a patch with Dualpaths for Mic on Return 1 and Guitar on Return 2. With the Studio Preamp and some Compressors, and a bit of Gain boosting, I get a great clean Mic signal.
My Patch as above is available on Customtone (free) at -
https://line6.com/customtone/tone/4433419/