Beginners question re attenuation

[Robert Murphy]

Hi all

I have an old mono TV, which doesn't have any sort of AV inputs or outputs.
It does have a front mounted speaker which seems reasonably accessable. I'd
like to have an output for both headphones and /or a line level out for the
amp, into which I could plug some headphones.

Is a simple resistor divider OK for this, taking the output to the speaker
and using a switched phono jack that I could mount into the case somehow?

Thanks
Rob


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[Rod Speed]

Robert Murphy <selectmax@hotmail.com> wrote in message
news:40058ed9$0$1745$5a62ac22@freenews.iinet.net.au...

I have an old mono TV, which doesn't have any sort of AV inputs or outputs.
It does have a front mounted speaker which seems reasonably accessable.

One thing to watch out for is that those older TVs often have
a hot chassis with full 240V on it and that will end up on the
addon speaker output jack if you dont allow for that.

I'd like to have an output for both headphones
and /or a line level out for the amp, into which
I could plug some headphones.

Is a simple resistor divider OK for this, taking the
output to the speaker and using a switched phono
jack that I could mount into the case somehow?

Attenuation wise, yes. Just watch out for a hot chassis tho.

 

[Phil Allison]

"Robert Murphy" <selectmax@hotmail.com> wrote in message
news:40058ed9$0$1745$5a62ac22@freenews.iinet.net.au...

Hi all

I have an old mono TV, which doesn't have any sort of AV inputs or
outputs.
It does have a front mounted speaker which seems reasonably accessable.
I'd
like to have an output for both headphones and /or a line level out for
the
amp, into which I could plug some headphones.

** When there is no AV connections and NO earphone jack then the odds are
very high the TV is one with a "hot" chassis. You cannot safely make *any*
audio connections to the circuit of such a TV set.

If you post the make and model of the set someone here may know for sure.




............. Phil

 

[Robert Murphy]

Thanks for the replies. I'm glad I looked before I leaped in here.

It's an NEC CT-2003MH, seems to be some sort of international model with
PAL/NTSC/SECAM.

Even if I don't 'touch' the chassis, and just use the two speaker terminals,
I guess one of those is going to be at, ahem, ground potential, is that
right?



"Phil Allison" <philallison@optusnet.com.au> wrote in message
news:4005d894$0$16593$afc38c87@news.optusnet.com.au...

"Robert Murphy" <selectmax@hotmail.com> wrote in message
news:40058ed9$0$1745$5a62ac22@freenews.iinet.net.au...

Hi all

I have an old mono TV, which doesn't have any sort of AV inputs or
outputs.
It does have a front mounted speaker which seems reasonably accessable.
I'd
like to have an output for both headphones and /or a line level out for
the
amp, into which I could plug some headphones.



** When there is no AV connections and NO earphone jack then the odds are
very high the TV is one with a "hot" chassis. You cannot safely make
*any*
audio connections to the circuit of such a TV set.

If you post the make and model of the set someone here may know for
sure.




............ Phil

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Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.560 / Virus Database: 352 - Release Date: 8/01/2004

 

[Phil Allison]

"Robert Murphy" <selectmax@hotmail.com> wrote in message
news:40060d6f$0$1752$5a62ac22@freenews.iinet.net.au...

Thanks for the replies. I'm glad I looked before I leaped in here.

It's an NEC CT-2003MH, seems to be some sort of international model with
PAL/NTSC/SECAM.

Even if I don't 'touch' the chassis, and just use the two speaker
terminals,
I guess one of those is going to be at, ahem, ground potential, is that
right?

** No way - both speaker wires will be at high potential.

Otherwise there would be a kinda loud hum don't you think ?




.............. Phil