Quick Help?? Wiring Shure WL183 mikes to Transit USB inter..

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Sorry for the !!, I need to get this running TodayIfPossible. And I'm
Way Out Of Town. Like Africa...

I have two Shure WL183's (Miniature Electric Condensers often used on
good body mike setups). I need to "run" them on an M-audio Transit USB
inteface on a laptop to do an unusual on-location recording tomorrow
(After midnight today your time).

The WL183's have 3 output terminals:

1 Ground
2 Bias (+ 1.5 to 10 VDC) [shown as connected to a FET Drain]
3 Audio Signal [Shown as connected to FET Source]

...so they ususlly have an external power of, say, +5V or so.

The M-audio Transit USB is a 24 bit up-to-96KHz 2-channel interface with
a 1/8" "Stereo" input connector. The manufacturer is not specific about
the input configuration, other than to say "Can supply DC for condenser
mikes". I measure +2.2VDC on each of the input terminals. It works OK
with a typical cheap 2-terminal electret mike.

So, HOW can I wire this up quickly??

?? Can I get away with grounding the "Source" (usually audio out) and
connecting the "Drain" to the Transit interface, like 2-terminal cheap
electrets??

?? If I supply + bias externally, like a 9V battery, must I insert a
blocking Capacitor (Sorry for the dirty word..) in the signal path??

?? Any other suggestions??

I hope some of you have encountered this issue before and can suggest or
point to information.

I gotta wire something up Real Soon.

THANKS!
Regards, Terry King ...On The Mediterranean in Carthage
terry@terryking.us

Archived from groups: rec.audio.pro (More info?)

In article <MPG.1c2a4bd03deb27ec9898c7@news.newsguy.com> terry@terryking.us writes:

> I have two Shure WL183's (Miniature Electric Condensers often used on
> good body mike setups). I need to "run" them on an M-audio Transit USB
> inteface on a laptop to do an unusual on-location recording tomorrow
> (After midnight today your time).
>
> The WL183's have 3 output terminals:
>
> 1 Ground
> 2 Bias (+ 1.5 to 10 VDC) [shown as connected to a FET Drain]
> 3 Audio Signal [Shown as connected to FET Source]

> The M-audio Transit USB is a 24 bit up-to-96KHz 2-channel interface with
> a 1/8" "Stereo" input connector. The manufacturer is not specific about
> the input configuration, other than to say "Can supply DC for condenser
> mikes". I measure +2.2VDC on each of the input terminals. It works OK
> with a typical cheap 2-terminal electret mike.

> ?? Can I get away with grounding the "Source" (usually audio out) and
> connecting the "Drain" to the Transit interface, like 2-terminal cheap
> electrets??

If you want to try powering it directly from the Transit, since, on
the Transit end, the power and audio are on the same terminal (the tip
of the jack) you'd want to connect the plug tip to the BIAS lead of
the mic, and a capacitor between the tip and the AUIDO OUT lead of the
mic. Probably something like a 10 uF electrolytic at the smallest
working voltage you can find. The + end of the capacitor should be
connected to the tip of the plug, so it sees the bias voltage.

If that doesn't work, you can always use a battery for the bias,
between the GROUND and BIAS leads. I wouldn't think you'd have to use
a blocking capacitor in this case.

It might be worth a phone call to Shure, just to be sure. They have
phones in Africa, right?


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.pro (More info?)

Thanks, Guys! Scott and Mike, this isn't the first time you've helped
ME out...

I do have emails into both Shure and M-Audio. Nothing in 24 hours, but
you've got me goin' already. Phones do work here in North Africa, now
that I have a USA callback setup. I can even call a US 800 number,
which was impossible from the local phone company. Surprise, I digress.

OK, I'm about to try the 'simple' common-source 2 wire configuration.
Someone else pointed to an online diagram of doing this:
http://www.uwm.edu/~type/Mic%20Pre [...] rcable.jpg
which is for a similar issue.

Bob, thanks for a clear explanation. I WILL try the external power and
source-follower configuration later. I'll get a chance then to compare
the two choices. I have a sound level meter so I can test with the same
acoustic signal both ways. In the longer run I really do want optimum
signal and low distortion.

Tomorrow I will be doing a 'simultaneous' 7PM UTC +- 10 Min. recording
with many other people in urban locations around the world. This will
typically include a local timepiece at 7PM. I will be recording the
ambience at the American Cemetery in Carthage, Tunisia, North Africa.
This should include some quiet countryside, medium-distant traffic, a
call-to-prayer from a Mosque, and the Cemetery Chapel bells at 6PM local
time.

Later, I'm planning to record both wildlife sounds and "SoundScapes" in
stereo at 24 bits with the Transit and a Laptop. The WL183 has a self-
noise of 22.5 Db SPL which is OK for an under-$100 mike. I'm hoping the
24 bit sampling will allow me to capture a wide range of input signals
for later processing. I've gotten spoiled with 24 Bit recording in
music production: I don't have to ride gain very actively for decent
results. I can cheat and do photography while multi-tracking a live
show. But that's ANOTHER subject; guilty as usual :-)

I'll try to follow this up with the results I get both ways.

Thanks for making me feel a lot closer to home.

--
Regards, Terry King ...On the Mediterranean in Carthage
....often In The Woods In Vermont
terry@terryking.us