RE: Sound card question
-----Original Message-----
From: Danny [mailto:mynixmail@gmail.com]
Sent: Friday, October 02, 2015 8:27 AM
To: debian-user@lists.debian.org
Subject: Re: Sound card question
> I believe that the output of the headphone jack is not impedance
> matched--I expect it's just a voltage source. Wat's more, unless you
> are plugging the same low-impedance devices into both Y outputs, _and_
> the source is impedance matched, you would not split the power
> equally. I don't know what you want to do with the second output, but it's
more than likely a relatively high impedance, so it would not load the
circuit at all.
> I could be wrong, but it seems logical to me.
>
> --doug
O.k ... let me explain why I asked the question for the sake of satisfying
any
curiosity:
I have EchoLink (Ham Radio VOIP) connected to Jessie like this:
VHF Transceiver (with two interface cables going to the MIC and LINE-OUT
jacks on the back of an internal sound card. Incoming audio (radio
frequency) goes through the antenna ... through the transciever ... to the
sound card (via the MIC interface cable) ... it gets processed by the sound
card and stuff happens on VOIP ... Because the VHF transceiver is
effectively turned into a repeater NO transmit or recieve audio can be heard
on the transciever itself (as it should be).
In order to hear comms coming in or out of the transciever (via an antenna)
one has to connect to the transciever with ANOTHER transciever in order to
hear people talk (if you are tuned to the same frequency off course)
Now ... my second transciever is fitted inside my car ... in order for me to
hear all comms on the frequency I need to go to my car and turn that
transciever on every now and then which becomes a pain in the donkey ... ;)
...
In order for me NOT to make a trip to the car every 10 minutes I though of
splitting the LINE-OUT and add a normal set of desktop speakers.
So ... I was just wondering if I will have any losses (in whatever form)
when I "split" the signal ... keep in mind that the audio signals processed
by the sound card should be strong and reliable ...
Thank You
Danny
Normally when a signal is "split" you should have "identical" impedences on
both sides of the split. Assuming this is so the resulting signal on either
side of the split should be down by 3db or "half". Normally the amplifiers
which are at the end of the split signal have enough gain so that 3db should
not affect the sound quality.
Larry
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