Odd extra long microphone plug on 7100

[Badger]

Hey classic mac fans,

Here's a weird thing on my old 7100--the microphone plug is a nonstandard length, and regular 3.5 mm miniplugs don't fit into the jack.  You can plug it in and only get one side, you can't get stereo in with a regular plug.  I googled this and found the following on LEM's web site:

"The old Performas (mine is a 6290 CD) had the slightly longer microphone plug, nonstandard in the audio world and unknown at Radio Shack."

So it seems someone else has run into this.  But I found no other references to this problem.  Anyone have any insight into this problem?  Barring an easier solution, anyone have an old microphone with the extra long plug that I could cut off and use as an adapter?

Thanks,

Guy McGrane

[Christian Wacker]

Apple's Proprietary Microphone is the only one that works in them. My
6100 is plagued with that problem as well.

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[Clark Martin]

Badger wrote:
> Hey classic mac fans,
>
> Here's a weird thing on my old 7100--the microphone plug is a
> nonstandard length, and regular 3.5 mm miniplugs don't fit into the
> jack. You can plug it in and only get one side, you can't get stereo in
> with a regular plug. I googled this and found the following on LEM's
> web site:
>

> "The old Performas (mine is a _6290 CD_
> <http://lowendmac.com/ppc/performa-6300.html>) had the slightly longer

> microphone plug, nonstandard in the audio world and unknown at Radio Shack."
>
> So it seems someone else has run into this. But I found no other
> references to this problem. Anyone have any insight into this problem?
> Barring an easier solution, anyone have an old microphone with the
> extra long plug that I could cut off and use as an adapter?

The PlainTalk Microphone had a longer than standard miniphone plug. The
extra length allowed for an additional contact which provided power for
an amplifier in the microphone. The remaining contacts are as for a
normal stereo headphone type plug. You can plug in a line level source
to the mic in jack of Macs that supported the PlainTalk (including the
PM7100).

Regular 3.5 mm miniphone plugs do indeed fit the mic in jack. If you
are only getting one channel then you have some other problem.

--
Clark Martin
Redwood City, CA, USA
Macintosh / Internet Consulting

"I'm a designated driver on the Information Super Highway"

[Badger]

Thanks for the replies.

When I use the microphone, I seem to get two input channels, because
audacity shows a level on each channel of the input. However, using
a standard miniplug only the left channel shows a level. Perhaps
there is corrosion on the jack. I'll try and clean it out, and see
if that helps.

About the extra contact for the power source, I'm looking at the plug
right now and it only has three contact surfaces that I can see, just
like a standard stereo miniplug, just each one is longer. Does that
mean the power contact is the same as one of the channels' positive
contact? If so maybe that is affecting the right channel somehow.

Guy McGrane

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[Clark Martin]

Badger wrote:
> Thanks for the replies.
>
> When I use the microphone, I seem to get two input channels, because
> audacity shows a level on each channel of the input. However, using
> a standard miniplug only the left channel shows a level. Perhaps
> there is corrosion on the jack. I'll try and clean it out, and see
> if that helps.
>
> About the extra contact for the power source, I'm looking at the plug
> right now and it only has three contact surfaces that I can see, just
> like a standard stereo miniplug, just each one is longer. Does that
> mean the power contact is the same as one of the channels' positive
> contact? If so maybe that is affecting the right channel somehow.

The jack on the computer has a sleeve, two ring and a tip connection.
The PlainTalk microphone is mono so the plug has a single ring that
connects to the two ring connections in the jack.

The sleeve is ground, the rings are left and right audio and the tip is
the power supply for the amp.

[M. Worgan, J.]

replace the jack (buy jack and plug [if needed] at Radio Shack)

 

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[Dan Knight, LowEndMac.com]

That's for Apple's PlainTalk microphone. I have a bunch. Please email
me privately if you'd like to buy one or more.

Dan Knight, LowEndMac.com

[Badger]

I'm a little sheepish to say but...

After fiddling around with the thing for some time, and taking a
really close look at the mic jack, I noticed the plug had to be
oriented with flat side up, or it wouldn't go all the way into the
jack, and wouldn't make proper connection. Also, the jack was off
center in the hole a little, which seemed to prevent a regular
miniplug from being fully inserted. So I kind of forced the plug in
a little to fully seat it and "PRESTO", it all worked perfectly, both
channels of input being recorded with their own levels fluctuating
individually. So its working for now, and I'll try to report if
there are any changes.

Sorry to trouble you with this trivial problem, but if there is a
lesson learned, its that the jack is pretty fickle, and can actually
work properly with a regular 3.5 mm miniplug, as long as the plug is
fully seated.

Thanks for all the suggestions.

Guy McGrane