In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf
wrote:
My early FM3 caused real problems when recording to my A77. Had to
fit a filter to it.

I haven't analysed the filter but it doesn't have an obvious 19k
'trap'. Just looks like a standard 3rd order LC design for a low pass.
I'd expect the 1310 to leak fair amounts of 19k, etc. That's why the
600s used a Toko filter, and perhaps why the FM4 does as well!


ISTR it being said the recorder should have the filtering - perhaps
switchable - rather than restricting the tuner audio output? For say
mono?

Clearly some makers/designers have thought that. :-) However my own view
is that it should be the tuner that suppresses anything that isn't intended
as audio from appearing the outputs. If nothing else, some people can hear
19kHz. And having a lot of ultrasonics isn't very kind to following
amplifiers, etc.

Personally I liked the Yamaha method. Have an active null to cancel out the
19k pilot, then use a Toko filter flat to about 17kHz to ensure good
behaviour up to 15k but still cut down the ultrasonic hash.

Slainte,

Jim

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