In article ,
Johny B Good wrote:
I'm not sure it was the storm that caused it - could just have been
coincidence. There is a third 2017 in the amp powered from the same PS
which is used as a mic amp when needed - but that wasn't plugged to
anything. It still works. Although it does have protection diodes across
its input because of the phantom power.

Although you didn't confirm how local the ground strikes may have
been, I don't think you can conclude anything else as to the cause of
the failure of _two_ amplifier chips connected to the same run of
cable (two balanced lines, screened or not, possibly a star quad
arrangement, but more likely the less elegant seperately screened
pairs configuration).

Ordinary twisted pair telephone cable. 20 twisted pair stuff. Giving 5
stereo circuits. No screen.

There were no lightening strikes nearby that I know of. There was some
forked lightening in the distance, but mostly the sheet type.

No sign of any burning anywhere.


Seems it's usual to use a pair of back to back zenners across each leg of
the input with this chip. I assumed that was only when used with phantom
power so omitted them. But am told they should always be used. ;-)

--
*A hangover is the wrath of grapes.

Dave Plowman London SW
To e-mail, change noise into sound.