Audio technica pro 45 wiring

[Peaveydisco]

I'm trying to work out the wiring for the Audio Technica pro 45. I've just inherited a couple without the XLR on the end - no biggy I'm sure. There's 5 conductors in the mic cable and obviously 3 pins in the XLR. There's 2 Red, 2 yellow and the shield, seems to be no conductivity between like colours or I'd just have twisted them together and cracked on. Don't really want to start peeling labels and dismantling the mics and so far I've found nothing online.  Any of you fine people have the answer, or have the mic and are prepared to have a look in the XLR for me 🙂

Edited July 12, 2023 by Peaveydisco
typo

[Simon Lewis]

The AT spec sheet shows this as being an electret condenser mic needing external phantom power and using 'two conductor shielded cable'.

Although it's a bit of a guess, I suspect that the cable fitted is Starquad (so yes, the two red and the two yellows would be commoned) but if there's no conductivity between the like colours then there's a fault in cable. 

[alistermorton]

Could it be that at some point someone has rewired with 4 core instead of 2 core and only connect one each of the red and yellow at the mic end. In which case it's trial and error to find the two connected cores.

[sunray]

21 minutes ago, alistermorton said:

Could it be that at some point someone has rewired with 4 core instead of 2 core and only connect one each of the red and yellow at the mic end. In which case it's trial and error to find the two connected cores.

Or even just use the reds (or yellows) as a pair

[alistermorton]

I was going to suggest that, but was worried that connecting the reds and yellows as pairs effectively put a dirty great aerial on the connector too. CMR should do it's thing, but I just wasn't 100% comfortable.

[Peaveydisco]

All good suggestions, there’s two of them and they both have the same cable, so whilst not impossible they’ve both been rewired I think it’s unlikely- labels are still well attached too which also suggests they’ve not been meddled with. Must admit I only put the meter in one of them though, I don’t know whether the second one is the same, will check that later on

[sunray]

1 hour ago, Peaveydisco said:

All good suggestions, there’s two of them and they both have the same cable, so whilst not impossible they’ve both been rewired I think it’s unlikely- labels are still well attached too which also suggests they’ve not been meddled with. Must admit I only put the meter in one of them though, I don’t know whether the second one is the same, will check that later on

When testing, make sure you are able to read (say) 20KΩ as I have known some devices using 4 resistors within the microphone rather than 2.

[Geoff49]

We have four of these mics over the stage as ‘Stage Listen’ feeds in our Am Dram theatre.
They have sounded pretty ropey and it was only yesterday I actually found out what they were - I was going to undo the xlr to see if they were balanced or not, but I could not unscrew any one of the four XLRs!

we start a new show tonight for 2 weeks so I was not going to investigate any further until it’s finished, but it was a coincidence that this got posted yesterday and I saw it once home! We are using two GZ500 boundaries as a stage listen for now.

Are the original XLRs really tight on these, I could not see a grub screw I the half-light?

As they are AT I presume they are fully repairable if found to be faulty?

…and the spec sheet suggests these should each be about 3m apart on our tiny stage - as we have four that’s impossible! Would they be better off as a pair and two boundaries, rather than all four? Or moving two of the ATs further back (they are above the front curtain at the moment).

I had planned to reposition them all once they were all working so would be interested to hear others opinions - PS sorry if it’s hijacked the thread!

 

when I’ve opened them I’ll be happy to give the OP the answer, if still needed in a couple of weeks!

[sunray]

It's just occurred to me the older version were not balanced phantom, instead they were unbalanced and required feeding with power on another wire. They were available with a pack to convert the standard phantom to a mini XLR. When purchased without the pack they came with no plug. Next thing the wires were also coated with something and stripping the coloured insulation rarely provided bare copper to test against, they did need heating with an iron and tinning to burn the melted (enamel?) insulation away.

I've just checked the offcuts of cable from some I installed sometime ago and yes I confirm they are 4C/starquad, in red & yellow. Some of my colleagues refused to terminate the cable.

As to spacing, I find for general coverage 3m is usually about where we end up but never specifically intended.

[Peaveydisco]

6 hours ago, Geoff49 said:

We have four of these mics over the stage as ‘Stage Listen’ feeds in our Am Dram theatre.
They have sounded pretty ropey and it was only yesterday I actually found out what they were - I was going to undo the xlr to see if they were balanced or not, but I could not unscrew any one of the four XLRs!

we start a new show tonight for 2 weeks so I was not going to investigate any further until it’s finished, but it was a coincidence that this got posted yesterday and I saw it once home! We are using two GZ500 boundaries as a stage listen for now.

Are the original XLRs really tight on these, I could not see a grub screw I the half-light?

As they are AT I presume they are fully repairable if found to be faulty?

…and the spec sheet suggests these should each be about 3m apart on our tiny stage - as we have four that’s impossible! Would they be better off as a pair and two boundaries, rather than all four? Or moving two of the ATs further back (they are above the front curtain at the moment).

I had planned to reposition them all once they were all working so would be interested to hear others opinions - PS sorry if it’s hijacked the thread!

 

when I’ve opened them I’ll be happy to give the OP the answer, if still needed in a couple of weeks!

No problem hijacking, the more we can find out about these mics the better 😀 - definitely would be interested to know how yours are wired, in the meantime good luck with the show 👍🏼

[Peaveydisco]

17 hours ago, sunray said:

It's just occurred to me the older version were not balanced phantom, instead they were unbalanced and required feeding with power on another wire. They were available with a pack to convert the standard phantom to a mini XLR. When purchased without the pack they came with no plug. Next thing the wires were also coated with something and stripping the coloured insulation rarely provided bare copper to test against, they did need heating with an iron and tinning to burn the melted (enamel?) insulation away.

I've just checked the offcuts of cable from some I installed sometime ago and yes I confirm they are 4C/starquad, in red & yellow. Some of my colleagues refused to terminate the cable.

As to spacing, I find for general coverage 3m is usually about where we end up but never specifically intended.

So, Sunray set me down the right path! 🙂

The flipping 4c cable is indeed enamelled or similar under the insulation - I tinned the end of all 4 cores separately and there is continuity between like colours. I've now put an XLR and tested - all good. Thanks for your all your assistance 🙂

Edited July 14, 2023 by Peaveydisco
typo...again

[sunray]

Well done. Sorry it took me so long to remember/realise/etc.

Did you have an issue with the soldering? Some of my ex colleagues never did get to grips with it.

[Peaveydisco]

19 hours ago, sunray said:

Well done. Sorry it took me so long to remember/realise/etc.

Did you have an issue with the soldering? Some of my ex colleagues never did get to grips with it.

It wasn’t too bad to be honest, good (probably too) hot iron seemed to do the trick. Thanks again for your help

[Geoff49]

When we used to have to solder the ultra-flexible headphone cables at the BBC - the ones covered in cloth or made with litz-type wire, we were taught to take a single strand of copper wire and tightly coil it around the stripped end of the cable in question, and then solder that.

[sunray]

3 hours ago, Geoff49 said:

When we used to have to solder the ultra-flexible headphone cables at the BBC - the ones covered in cloth or made with litz-type wire, we were taught to take a single strand of copper wire and tightly coil it around the stripped end of the cable in question, and then solder that.

This seems to be quite a standard method but other than making something bigger to solder I've never worked out what the benefit is, the fabric still melts.

The cable on these mics is basically a standard, but very fine, stranded copper albeit the strands are coated.