Hi Andy,
You will find the answer to your question under the “Master” control section “11. TONE Cut control, as you can see where this differs from a treble control is that it’s placed in the power amp section, in practice this works in conjunction with the Master channel level rather than the preamp, so setting these levels will influence the way in which high cuts work, see the previous video I posted:
https://www.voxshowroom.com/ct/amp/us/m ... Manual.pdfMy Laney Lionhearted works in as similar way, you will see how this is described under tone control (number11) in the manual below:
https://manuals.laney.co.uk/L20T-112%20 ... ual_EN.pdfI mainly use plugins these days, one I of the reasons I chose Helix Native for amp emulation and FX is because it captures these features extremely well.
Regards
Gary