Hello!

I am a new and a bit inexperienced AV Tech at a school.

I've been asked to connect an NAD Stereo Amp model 3130 which has 5-way binding posts to 2 speakers which only have XLR inputs.

Is it possible and if so what pins on an XLR male connector do I solder the speaker wire cables to?

Thanks in advance - cause I think I might be using this forum a lot in the coming months!

Squircle

This is probably a bad idea. Speakers with XLR inputs generally have built-in power amps. What speakers are they? Show a pic of the back panel.

Hi Thanks for your reply.

The speakers are Carlsbro Beta 115 300 Watt Passive.

I'm at work and IMGUR is blocked so I'll upload a picture when I get home.

https://www.picclickimg.com/00/s/MTIwMFgxNjAw/z/l-YAAOSwzsxdcNzU/$/Carlsbro-Beta-115-Speakers-_57.jpg

It's the same as that though!

Squircle

Looks like they replaced the speakon connectors with XLR. Bad idea.
Maybe this will help.

Hopefully you have a DMM (an AV tech should, right ) that you could probe the speaker input pins to check for the resistance of the speaker coil and those would be the pins to wire to the XLR. Be sure to wire each XLR the same, so the polarity might be the same presuming they didn't hose up polarity in the connections within the speakers.

Older Ampeg amps used to use a XLR type cable with maybe 4 pins? I remember them being a super pain in the ass. If you accidentally leaft the cost at home when gigging you were up the proverbial creek without a paddle.

I agree with others, they likely had Speakon connectors and switched to XLR. If they were also using Mic cables to connect cabs that's a really bad news. Standard mic cables are designed for super low current Mic and line levels. You go connecting a 1000W power amp and forcing some heavy duty current and you'll fry those cables from the inside out. Using any signal cable for speakers is the #1 cable killer and as the cable overheats and melts the insulation inside they can allow oxygen in and corrode, become microphonic and crackley as the copper oxidizes if not a complete short which can instantly blow a SS power head.

You can use an XLR cable for speakers but you'd have to make your own cables which would be a super PITA. Main problem is speaker cable has to be heavy gauge and most XLR cables simply haven't got enough room to fit the cable into them and do a good solder job.

Its by far easier to buy factory made speaker cables and just fix the jacks on the cabs. This way it works with standard cables in case you have one go bad and need to swap them. You'd need to pull the current jacks plates out then measure the size of the hole in the cab, then find something that will take 1/4" jacks. I buy cabinet hardware here, they have everything you might need at dirt cheap prices. The plates are $1.50 each and 1/4" jacks are $1 each. $7, problem solved.
If you had to buy XLR jacks they are around $6 each then you have to buy some heavy gauged cable in bulk. It can wind up costing allot of money plus you have to be a whole lot better at soldering cables to XLR jacks compared to soldering speaker wires to 1/4" jacks.

Plates - https://www.parts-express.com/cat/connector-dishes/646

Jacks - https://www.parts-express.com/neutri...tched--092-122

25 or 50' cables - https://www.parts-express.com/neutri...tched--092-122

There may be XLR connectors made for speaker size wire. If you can find something like that it will be more do-able.
If you pull off the XLR panel at the speaker you'll be able to see the pin wiring.

What's so PITA about making a cable?
Assembling an xlr for speaker cable is a third less hassle than wiring for Mic cable.

It's a proven, rugged, solid connection.
Just because it's not common doesn't make it a bad idea.

My AKG LSM-50s (passive) have xlr inputs.
I used fairly heavy gauge Sommer cable and neutrik connectors and have way more confidence in the longevity of those than I do the banana plugs at the amp end.