Definitions are normal but some of them require a positive to negative switch(or vice versa) before entry in the grid, as indicated in their clue's wordplay. I think the word length may be altered too.
8d Instrument's uplifting tune's beginning, no awful note produced (11)
11a Suspect couple bound to be uncertain, legally (2,5)
//Definitions for all the solutions are normal, but some of
them require a positive/negative switch (or vice versa)
before entry in the grid, as indicated in their clue’s
wordplay.//