Is it always preceded by a pop , ala
http://recording.org/controllers-aud...17-yamaha-stag
epas-300-problems.html

Then genuine or false protection issue ? pops due to protection cutting in
or preceeding the protection ?
Ignoring the internal to ps protection . Both the outputs are monitored for
protection and only the +rail , presumably an advantage of antiphase
operation. If no PbF issues and no blown amps then I suppose a stopgap
measure would be to downgrade the output end pick-offs by a half or so,
until a fully known cause is found