[TenTec] Pegasus line out

[Duane Grotophorst]

Paul has explained it well.

However one thing to keep in mind is that there are
some sound cards that do not like having both the
"left" and "right" inputs tied together without some
degree of DC isolation between them. The line out
arrangement on the Pegasus has 100 ohms between L&R
(tip & ring) so will quite likely avoid this potential
problem when using a simple stereo mini cable
extension.

If you do go that route I would go ahead and just try
it first, but if it doesn't work then dig a little
deeper and investigate what the sound card's behavior
is when L&R are tied together.

Either way I always use an isolation transformer to
reduce the chance for ground loops etc. So I shy away
from using just a simple cable regardless.

Duane
N9DG
EN53bj


--- Paul Christensen <w9ac@arrl.net> wrote:
> > This is something I have thought was odd since I
> received my first Pegasus. The standard cable that
> came with the Pegasus to
> connect the line out ( to the soundcard iin my case)
> is a stereo mini phono. Without tearing apart the
> rig, is the jack really
> stereo and if so what is the purpose?
> 
> The Line output is dual-mono in the sense that the
> same audio appears on the jack's tip and ring with
> respect to ground (shield).  I
> assume it was designed this way since most sound
> card inputs are true stereo with separate left and
> right audio channels.  Ten-Tec
> gave us the ability to run the Pegasus' mono audio
> into both the left and right sound card inputs.
> 
> > If I connect the cable to something that is mono
> it bridges the left and right together and
> attenuates the output.
> 
> That's right.  In this configuration, you have
> shorted the "ring" on the plug to ground when
> terminating the opposite end into a
> true mono mini jack which also grounds the tip since
> they are tied together (or through a low-value
> isolation resistor).   In either
> event, the audio is shorted to ground.  FYI - Radio
> Shack sells 1/8" mini stereo/mono adapters to help
> with this problem if you need
> to terminate the Line out audio into a tip & sleeve
> plug or jack.
> 
> -Paul, W9AC


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