Legacy microphone connectors

At one time most mics used their own specific connectors. These can be obsolete.

If say your mic cable has non XLR at both ends simply cut it and fit XLRs. You can then either plug those together and it will work as before, or insert an XLR extension. Ebay is quite a good source of 3 pin XLRs.

Note mic cables don't follow normal practice in that the mic input on the amp is female. This is because of powered mics which normally run on 48v DC - so prevents you touching live pins. In other words the XLR on the mic has pins, a male.

XLR connections are thus

2

And marked as such.

I'm an idiot - should be

The whole point in posting it is it doesn't look logical. ;-)

Dave, with swapping the pin config I think the hot/cold got swapped too. XLRs are normally:

Charles F

Yes. Sorry about not correcting that too.

The idea of that pin configuration is being able to link 1 (screen) and 3 (cold) easily for unbalanced connection. I think.

In article , Dave Plowman (News) scribeth thus

But if the other end is wired the same then no difference;)...

Indeed - but not good practice, when you may not be able to see or check the other end of a cable, esp. in fixed installantions.

Charles

In article , AnthonyL writes

Back on topic, what you have sounds like a Reslo connector, used by them and Grampian (IIRC) and a few others in the 1960s and 1970s.

They're identifiable thus:

- the pins are fatter than those of XLRs, but still in a fairly even triangle

- there's a clamping ring with a screwthread, and

- a fat indexing lug on the side of the connector (around 1/16"), and a slot cut in the side of the mic receptacle (not a groove per XLRs).

It's just possible that it's a Coles connector - that has the three pins in a flatter triangle, almost a straight line. There's no clamping ring, but a slot at right-angles to the connector (there's a pin in the mic that catches in this to lock the connector in place.

The Reslo/Grampian style were common in the BBC and elsewhere for lower-grade mic uses such as talkback. You often found them on the end of goosenecks. Mics using that connector were in production well into the 1980s, pretty much all were unpowered, moving coil.

The Coles ones are still current, for a very small range of mics (4038s), as they're retro-styling and buyers like that consistency.

As others have suggested, you can simply cut the cable and insert XLRs to extend it or shorten it as much as you wish.

Ribbon mics were often made to 30 Ohms. This was for two reasons: it was an early mic impedance standard, because it worked well on long twisted-pair cable runs (lower losses), and, because ribbons have an extremely low resistance, the impedance-converting transformer at the mic end could be cheaper (the bigger the impedance change in one jump, the harder it is to make a suitable audio-grade transformer).

Prior to XLR ubiquity, BBC studio wallboxes used to use Cannon EP-8 connectors for mic cables. The eight pins included connections to an impedance matching transformer built into the wallbox, specifically for low-Z mics, so the mixer only saw around 300 Ohms. So the mic cable wiring went to different pins on the EP-8 depending on its impedance!

If your (Reslo?) mic still works, there's a good market for it on eBay, but you'll need to sell it with the transformer, otherwise the buyer will probably wonder why the output is low and covered in hum!

S.

I remember by saying to myself 'Screen-Line-Return', Pins 1-2-3, 'SLR', which is pissed talk for 'XLR' :-)

And the Japanese use the opposing sex, males for inputs, females for outputs. A few OB companies use the same sex for everything on their tailboards and external cable reels, that way they can never have the cables the wrong way round !

Wouldn't that correctly be called an STC connecter? Coles being the later owner of the brand?

FWIW, that connector is called a thistle at the BBC as it first appeared on the STC moving coil apple and biscuit or thistle mic. 4021? Also used on the classic 4038 ribbon and 4033 'guiness bottle'.

In the early days of XLR, they were used in the conventional way. Ie, the output being a female. It was only when phantom power arrived that it was changed round for mics, for H&S reasons. Using XLR for things like 100v line speakers followed the original convention - as did some line level things like tape recorders. Basically rather confusing. ;-)

Also, a female 'Telefunken figure of 8' power connector is a perfect fit for the two 'horizontal' pins in a 3-pin XLR male.

A colleague had to attend to the charred remains of a cheap mixing desk that had the lethal (literally) combination a figure of 8 power connector, and someone plugging it up blind, by reaching over the back.

In article , "Dave Plowman (News)" writes

Probably, but available from Coles now. I'm not sure if the latest 4038 incarnation is that or XLR - I suspect it's still the old one.

Yes. There's one on the 4021 I own. Time was when they were 'bowled' up over the girders of the stand roofs at football grounds for crowd FX* - handy to have a strong plug-socket combination in that context.

S.

• usually the version with the integral windshield - can't remember the type #.

Luckily that figure of 8 mains connector was never used on pro gear. Which would have an earth too.

I do remember the changeover in the BBC Film Units which was in the

Jim.

Well there is no excuse anyway:

"Always run away with the female"

or for female sound assistants:

"The male end goes in".

Far worse was Anglia TV - they used the wrong sex for LNE mains. So OB types had to carry adaptors for use on shared sites.

So in the late 60s did BBC RD.

In article , Charles F scribeth thus

No course not but I have seen them wired with just white cables so a continuo check was needed to determine polarity...

I think you meant "Gender Benders". In fact, you seem to have misused 'sex' for 'gender' elsewhere in your post. :-)