Gareth Magennis wrote in message
...


"N_Cook" wrote in message
...
with USB connected but no active pc. Hash on both channels of headphone
monitoring, cycling through on about 1.1 sec period. Worse when phantom
is
on so maybe something with the 5 to 48V generator. Will try a few IC
numbers
to check DC rails, check ESR of caps and disable unused 48V supply is
about
as far as I will go.




Isn't the Mbox Mac only?



Gareth.



It was working with whatever flavour of pc until this hash developed. No
trace of 48V anywhere. XLR mic connections traced via 6.2K droppers back to
the rectifier diode of the buck converter. Looks as though the output is
gated rather than converter switched on and off for phantom. Will try
locating data on this dodgey looking labelled soic and cut its supply anyway
and hope it is not monitored by anything