Then it's possibly a matter of signal-level...  A correct line-out is
supposed to have a signal level of 0.5 volts.  A headphone jack will have an
amplifier that gives a level of probably 2-3 volts to drive the headphones.

You probably need the volume on the stereo a lot lower when using the
headphone-output instead of the line-out, so you may try simply dampening
the signal in a voltage-divider to correct this.
I assume your system wants about 16 Ohm load, so use a 16-32 Ohm stereo
pot-meter and couple it between the signals and ground.  Now take the
variable outputs from the potmeter and wire to your stereo.  To avoid
DC-coupling between them you could also add a very large capacitor in series
with the signal.

Good luck.

    KreAture

----- Original Message -----
From: "Chris Rocco" <crocco@CORP.EARTHLINK.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Sunday, March 02, 2003 2:06 PM
Subject: Re: [EE] Headphone out to RCA line-in converter


> (thanks for the speedy reply)
>
> My portable CD player has the same issue when I use its headphone jack
> -- but it happens to also have a line-out jack that works perfectly
> (meaning that there is no hiss when I use the line-out jack).  This
> leads me to believe that there may be a [simple] solution out there...?
>
> Chris
>
>
> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Kyrre Aalerud
> Sent: Sunday, March 02, 2003 5:11 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE] Headphone out to RCA line-in converter
>
> I'd say this is due to either noisy power-source, or noise from the
> hard-drive or similar.
>
> Most likely, you can't filter it out either because it will be in the
> part
> of the sound-spectrum you wish to hear.
>
>     KreAture
>
> ----- Original Message -----
> From: "Chris Rocco" <crocco@CORP.EARTHLINK.NET>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Sunday, March 02, 2003 1:39 PM
> Subject: [EE] Headphone out to RCA line-in converter
>
>
> > I would like to connect my laptop's headphone jack to my stereo's RCA
> > input jack so that I can hear MP3's and video files on my stereo/TV --
> > the problem is that I get a hum when I use a direct cable, even when
> > there is nothing generating any sound on the laptop.  Is this due to
> an
> > impedance mis-match?  How can I fix it?  I can't seem to find any
> > circuits on the Internet, but I'm sure that they must be out there...
> :)
> >
> > Thanks in advance,
> > Chris
> >
> > --
> > http://www.piclist.com hint: To leave the PICList
> > mailto:piclist-unsubscribe-request@mitvma.mit.edu
> >
>
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