Thanks for help Chris,
robb

"Christopher Ott" spamtrap at ottelectronics dot com wrote in
message ...
7805 needs about 2 volts of clearance to maintain regulation.
Data sheet for
the 3 manufacturers I looked up shows it needing at least 0.3uf
on the input
to prevent oscillation (which is what is causing the noise on
your input
peaks), however you should use a much larger cap on the input
to smooth out
the ripple from the bridge as well.

Linear regulators can be picky about their needs for
input/output caps. It
varies even more with LDO types. Even the type of cap matters
with some of
them...