Old School: Wiring Amphenol MC3M to Male XLR

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Newsguy <news@news.com> wrote:
>Hi there. Here's a question for the "veterans" in this newgroup. I have an
>old Shure 55s microphone (the Elvis type). This microphone uses an old
>school version of a modern XLR connector known as an Amphenol MC3M. This is
>a three pin arrangement (pin 1, pin 2, pin 3).
>
>Now, I have a brand new old-stock Amphenol MC3M connector, a brand new
>modern male XLR connector, and a length of mic cable. I want to put it all
>together and make a functional mic cable. Do I simply go pin 1 XLR to pin 1
>Amphenol, pin 2 to pin 2, and pin 3 to pin 3?

No. I forget the pinout offhand, but get an ohmmeter. You will find one
pin goes to the case. That one goes to pin 1 on the XLR. The other two
have no connection to the case but have fairly low resistance between them.
Those go to pins 2 and 3.

>I have tried to locate this information through Google, but I cannot find
>anything that shows a proper diagram. As a sidenote, this 55s mic has a
>three way impedence switch (L-M-H), and I am not sure if that factors into
>the way the cable would be soldered up.

Actually, if you go to the Shure web site, and look at the discontinued
products page, you will be able to download the original data sheet for
the mike, with the schematic and everything.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

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

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cuehhq$di1$1@panix2.panix.com...
> Newsguy <news@news.com> wrote:
>>Hi there. Here's a question for the "veterans" in this newgroup. I have
>>an
>>old Shure 55s microphone (the Elvis type). This microphone uses an old
>>school version of a modern XLR connector known as an Amphenol MC3M. This
>>is
>>a three pin arrangement (pin 1, pin 2, pin 3).
>>
>>Now, I have a brand new old-stock Amphenol MC3M connector, a brand new
>>modern male XLR connector, and a length of mic cable. I want to put it
>>all
>>together and make a functional mic cable. Do I simply go pin 1 XLR to pin
>>1
>>Amphenol, pin 2 to pin 2, and pin 3 to pin 3?
>
> No. I forget the pinout offhand, but get an ohmmeter. You will find one
> pin goes to the case. That one goes to pin 1 on the XLR. The other two
> have no connection to the case but have fairly low resistance between
> them.
> Those go to pins 2 and 3.
>
>>I have tried to locate this information through Google, but I cannot find
>>anything that shows a proper diagram. As a sidenote, this 55s mic has a
>>three way impedence switch (L-M-H), and I am not sure if that factors into
>>the way the cable would be soldered up.
>
> Actually, if you go to the Shure web site, and look at the discontinued
> products page, you will be able to download the original data sheet for
> the mike, with the schematic and everything.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Hi Scott. Thank you very much much for your quick and informative reply. I
am on track now. However, here's one that is a little confusing: I found
an old cable in the bottom of a drawer that has the above-mentioned amphenol
on on end and a 1/4 phone jacl on the other. So, I cut off the 1/4 jack and
was going to put on a modern XLR. After I cut the cable, I noticed that
this cable only contains one inner wire and the "shield". In other words,
we have only two conductors here to connect to the modern XLR. Now, perhaps
the shield goes to pin 1 of the xlr, but then we have only one conductor
left over.

Does the one that's left go to XLR pin 2 or XLR pin 3?

By the way, I checked the Shure web site and found the document you were
referring to, thank you. But with my extremely limited electronics
knowledge, it really makes no sense to me.

Darren

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

In article <fJMOd.20632$Ka6.141152@news1.mts.net> news@news.com writes:

> I found
> an old cable in the bottom of a drawer that has the above-mentioned amphenol
> on on end and a 1/4 phone jacl on the other. So, I cut off the 1/4 jack and
> was going to put on a modern XLR. After I cut the cable, I noticed that
> this cable only contains one inner wire and the "shield". In other words,
> we have only two conductors here to connect to the modern XLR. Now, perhaps
> the shield goes to pin 1 of the xlr, but then we have only one conductor
> left over.

That's a cable that's designed to be plugged into a "high impedance"
input, with the switch on the microphone set to the high impedance
position.

> By the way, I checked the Shure web site and found the document you were
> referring to, thank you. But with my extremely limited electronics
> knowledge, it really makes no sense to me.

In that case, you probably wouldn't understand the explanation, but
if you disassemble the connector on the microphone end of the cable,
you'll see how it's wired.

You really shouldn't use that cable with an XLR connector, but if you
insist, connect the center conductor to pin 2 and connect the shield
to pins 1 and 3. Be sure to turn the switch on the mic to M or L. Then
plug it in, and when you hear how bad it sounds, you'll have second
thoughts about whether it's worth the time and trouble to make the
proper cable.

Someone gave me two 55s and when I listened to them, I decided that
when I find a nice piece of walnut to mount them on, I'm going to turn
them into a hat rack. I could probably make a killing selling them on
eBay but I want to spare someone else the agony.




--
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?)

In article <8vadnVmLHbPQdpbfRVn-gA@omsoft.com> nopsam@nospam.net writes:

> He'll still want it on H because that's only about 150 ohms anyway. M
> and L are something like 50 and 25 and those positions really DO sound
> terrible. If you add some HF eq, the mic sounds a little better.

There were several models of the Shure 55. I'm pretty sure at least
one of them had a real step-up tap on the transformer so it could be
run into a high impedance lower gain mic input that was typical of
"the day."



--
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?)

Mike Rivers wrote:

> In article <8vadnVmLHbPQdpbfRVn-gA@omsoft.com> nopsam@nospam.net writes:
>
>
>>He'll still want it on H because that's only about 150 ohms anyway. M
>>and L are something like 50 and 25 and those positions really DO sound
>>terrible. If you add some HF eq, the mic sounds a little better.
>
>
> There were several models of the Shure 55. I'm pretty sure at least
> one of them had a real step-up tap on the transformer so it could be
> run into a high impedance lower gain mic input that was typical of
> "the day."


And as OT confirms later, once again I am full of it. I wonder where I
got that...? Maybe it'll sound better now.