🚀 go-pugleaf

You can keep the volume at the TV headphone jack high enough for
person with hearing loss and avoiding 60 Hz buzz by cutting down on
the volume in the set's speaker.

One thing you can try is to switch the speaker in your set to a
speaker in series with a resistor.  You need to watch the impedance
of the combination.  If the set has a 16 ohm speaker, try replacing
it with an 8 ohm speaker in series with an 8 ohm, 5 watt resistor.
You could keep the original seaker by placing the speaker in
parallel with a 16 ohm resistor and that in turn in series with an
8 ohm resistor: that would make sure that the impedance stayed the
same.

There are a zillion different types of audio outputs in TVs.  Some
sets use class A outputs driven from very high voltage (135 volts)
and 40 ohm speakers.  Other sets are more "normal".  You should be
very careful if you consider digging around inside your set.  On a
lot of color TVs, the audio circuit contains components that are
**NOT** isolated from the AC input.  There is a chance you might
get seriously zapped if you don't know what you're doing.  I'd
recommend getting the schematic for your set first, so that you can
assess the saftey of any modifications you might make.

You might try using an operational amplifier chip to make a notch
filter for the 60 Hz buzz for the ear phone listener.  You should
be able to find the design for a 60 hz filter in the applications
notes in an integrated circuit catalog.  I think the spec sheet for
the National Semiconductor LF444 or Texas Instruments TL-072 should
have and example notch filter.

  --Bill  (wtm@neoucom.UUCP)