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From: lacasse@randvax.UUCP
Newsgroups: sci.electronics
Subject: Re: need advice on TV sound amplifier
Message-ID: <966@randvax.UUCP>
Date: Tue, 5-May-87 21:54:33 EDT
Article-I.D.: randvax.966
Posted: Tue May  5 21:54:33 1987
Date-Received: Fri, 8-May-87 03:57:04 EDT
References: <578@stracs.cs.strath.ac.uk> <566@neoucom.UUCP> <1272@genrad.UUCP>
Reply-To: lacasse@rand-unix.UUCP (Mark LaCasse)
Organization: Rand Corp., Santa Monica
Lines: 26

One person asked for help where the sound level in the headphones plugged
into a TV for a hard-of-hearing person was insufficient when the volumn
control was set at a confortable level for other viewers to listen on
the still-connected speaker.

Someone replied and suggested attenuating the speaker inside the set.
He cautioned of electrocution and other risks of altering the set.

I re-iterate his caution: don't modify a TV set if you are not "qualified
service personnel".

But it is interesting to note that many TV sets have a resistor in
series with the headphone jack to attenuate it.  I suspect they do this
to make the volumn control more usefull for the headphone listener.
Since in your set the speaker does not cut off when a headphone plug
is inserted (most do), the manufacture may also attenuate the headphone
plug in the hope of making the speaker and headphone level more
commenserate.  In general, a headphone takes a LOT less power then
a speaker.  If your set has such a resistor, you might be better off
it if wasn't there (shorted out).  Then you could use a simple "L-PAD"
(100 ohm 5 watt potentiometer) in series with the headphone, near
the headphone, adjusted by the hard-of-hearing person.  You might
want to take your TV to a good repair center and ask if this modification
could be made.

    mark