FC6 82801G sound

[Tim]

On Wed, 2006-12-20 at 20:39 -0800, Les wrote:
> There are two or three sizes of those stereo mini plugs, and the
> metric ones NEARLY match SAE measurements, however since they are not
> quite right, they sometimes short out the plug.

That's the first I've of there being metric and non-metric ones, but I
wouldn't be surprised.  And I've certainly come across crap ones (with
over-bulbous ends, and the rings in not quite the right places).  All of
which are different than the original telephone operator jacks still
used on professional jack fields.

I can't recall the proper name for them, just their industry-given
nicknames (a TT plug, PMG plug, & quarter-inch TRS), but the small
version was known as a "Bantam" plug, and you can see them here:

<http://www.pomonaelectronics.com/images/large/4280.jpg>
(the Bantam plug on the bottom)

The full-sized version looks the same design as the Bantam, and is
almost the same size as the 6.5 mm headphone/microphone plugs.  Neither
of which are really compatible with modern phone jacks, the large one
often not connecting with the tip or ring contacts, an the Bantam one
being a completely different size.

> The outer shell (the shaft of the stereo plug) should be
> common ground, and the ball of the stereo plug should be right (if I
> remember correctly) while the tip of the mini plug should be left.

With tip, ring, and sleeve, unbalanced, stereo connectors, whatever the
size plug, the standard is:

    Tip:  Left
   Ring:  Right
 Sleeve:  Ground

For balanced mono connections, tip and ring are the signals (usually hot
on the top), sleeve still being the ground.

There's a brilliant picture of this about 2/3 down this page:
<http://en.wikipedia.org/wiki/Phone_plug>


> If ground is mistakenly connected to either of the other two, the
> result will generally load the amplifiers so much that no sound (or
> very little) comes out.

I'd say that rarely happens.  Usually, if you short out the left size,
for instance, the right side will still work as normal.  Remember that
most headphone sockets are not driven with much power.

> Another problem comes when a mono plug is inserted into a stereo
> socket.  The mono plug will short out the stereo amp. 

No.  It'll short out the right channel, and do nothing to the left
channel.  Most headphone amplifiers hand that in their stride.

-- 
(Currently testing FC5, but still running FC4, if that's important.)

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