Yeah! Thanks guys, this is what I've been looking for. This PDF supplemental note explains it!

Jerry, You're right. WG2 affects WG1 and not backwards. That's What it says in the note too. You rightly mentioned that this is badly described in the user manual.

I figured whether we should report this to the Roland Company, but they'll probably treat it as a minor issue anyway...

Still my doubts about the TVA (first problem) are not really gone, I still don't see the way in which TVA1 acts when using a booster.

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