XLR (balanced line level) to RJ45 - another DIY question

[david.elsbury]

Thanks

I'm quite sure that I can get away with a 75hz low pass - no need to go down to 30hz, if I do then there are better solutions available!

 

Have used the Neutrik NTE-1 quite a bit in the past for small projects, and very happy with it. Might try and source some more. When a transformer saturates, is it audible to the rest of the signal path? Or does it just "drop" the frequencies that are too low for it?

 

Cheers :)

[GaryNattrass]

Yes I know balanced line level and mic level will go a long way but in broadcast we use screened star quad to transmit it with audio connectors such as XLR and military multi pin amphenols not a telephone connector.

There seems to be a drive towards using domestic and telephony based connectors these days and whilst it may work I personally would not be using such connectors for any critical interfacing that may get damaged in use or worse cause interference or potential faults that could affect a critical piece of kit.

I am seeing all sorts of telephone connectors being used for pro digital interfacing including the ISDN and com boxes I use on major sports events and I tend to find that I have to be very careful in protecting them or make them more robust with the addition of cable ties or tape wrap.

I also question some of the fibre optic connectors that we are being forced to accept but that is another story.

 

The 15 min quote is a tribute to Andy Warhol by the way.

[Bobbsy]

Yes I know balanced line level and mic level will go a long way but in broadcast we use screened star quad to transmit it with audio connectors such as XLR and military multi pin amphenols not a telephone connector.

There seems to be a drive towards using domestic and telephony based connectors these days and whilst it may work I personally would not be using such connectors for any critical interfacing that may get damaged in use or worse cause interference or potential faults that could affect a critical piece of kit.

I am seeing all sorts of telephone connectors being used for pro digital interfacing including the ISDN and com boxes I use on major sports events and I tend to find that I have to be very careful in protecting them or make them more robust with the addition of cable ties or tape wrap.

I also question some of the fibre optic connectors that we are being forced to accept but that is another story.

 

The 15 min quote is a tribute to Andy Warhol by the way.

 

 

No we don't. I only ever used Starquad for mic level runs via electrically noisy areas (and that was "belt and braces" rather than an absolute necessity).

 

For any balanced line level stuff I'd usually use a basic FST (foil screened twin) or a multicore with similar properties. However, by the time of my retirement we were starting to use Cat5/6 cable and "flood wire" a facility with cable that could carry data, telephony or balanced audio depending on the termination. It worked a treat and gave huge flexibility.

 

(The second last place I built using the above cable philosophy contained well over 100 km of various audio cables all under the one roof--and we never had a single issue with noise or crosstalk--or at least not problems that couldn't be traced to the gear attached. We also achieved IBA approval for live use on the ITV network on our first try--back in the days when there was such a thing as IBA approval! Oh, how things have slipped now. :( )

[david.elsbury]

There seems to be a drive towards using domestic and telephony based connectors these days and whilst it may work I personally would not be using such connectors for any critical interfacing that may get damaged in use or worse cause interference or potential faults that could affect a critical piece of kit.

Granted, RJ45's are a plastic connector, (Ethercon's aren't, which is why I intend to put them into my boxes) and they are not "designed" to carry audio... but they are designed for computer networking, which I regularly use on shows - as long as the clips are intact and in good condition, I never have any problems with the connector. I'd say this was "critical interfacing" ;)

 

David

[Bobbsy]

I bet there are a few RJ45s in the chains that control our electricity provision, cellular networks...or even the American nuclear launch capability!

 

I probably wouldn't use an RJ45 in a position where there was constant plugging and re-plugging or where, for example, phantom power had to be passed. I also wouldn't even contemplate CAT5/6 for unbalanced circuits...but outside those exclusions it works well.

[Brian]

For any balanced line level stuff I'd usually use a basic FST (foil screened twin) or a multicore with similar properties.

 

Luxury! We used to use a lot of BBC style PIN for line level jackfields. For those not in the know that's multiple twisted pairs with an overall screen.

[Bobbsy]

Yeah, but I had to walk 20 miles barefoot through the snow to get my FST! :)

 

Edited to add: is that similar to what Canford would call KSM (BBC PSN20/4)? If so, yeah we used a lot of that between Krone frames and jackfields. The better stuff was for longer runs because our weird building layout gave us a tech floor split into two halves with an awkward cable route between those two halves that doubled the direct distance.

[Brian]

is that similar to what Canford would call KSM (BBC PSN20/4)?

Yes. I'm getting my PIN and PSN mixed up.

 

PIN is individual screened pairs.

PSN is overall screened pairs.

[david.elsbury]

So I purchased some Ethercon connectors off ebay, which arrived yesterday.

 

And I learnt that D size (which the panel is punched for) is slightly larger than B size (which happens to be the connector style that I ordered) :(

 

Anyone got any suggestions about making B size connectors fit into a D size hole?

 

Thanks...

David

[MarkPAman]

B size (which happens to be the connector style that I ordered) :(

 

If it helps, you are not the only person to have done this :(

[david.elsbury]

Have re-ordered some D size Ethercons, figure if the job is worth doing it's worth doing right- especially since the connectors mount from the rear of the panel, anything I do to it won't result in as good a punch as what is there already.

 

Just waiting for the mods to approve my For Sale post. The B's are up on ebay. Here's hoping someone takes them!

[david.elsbury]

So; project complete.

 

I first purchased B size not D size Ethercons. Then, the next lot I got were PCB mount only and I tried to solder to the pins directly - and ripped one out.

 

Third time lucky? Well, I got some of the Krone 110 Punchdown style connectors - unfortunately the punchdowns make the plate too tall for the backbox. So I ripped them off the board and soldered directly to the boards. What a mission!

 

I had to purchase longer screws to fit the plates to the backboxes. Inexplicably the ones supplied were too short?!? And I had to mount the Ethercon in position 3 not 4 - too close to the screw pillar for the front panel fixing.

 

No transformers involved, Ch 1 & 2 have a single XLR and TRS jack. Ch 3 is an XLR and 2x TRS jacks.

 

Total time involved: far too long. Would do it again, with some modifications... but still cheaper than a commercial product :)

 

http://i39.tinypic.com/2r38ab6.jpg

 

http://i44.tinypic.com/2j1rmhh.jpg

 

David.

Edited January 9, 2014 by david.elsbury

[antlear]

do you have a picture of the insides?

 

do they work ok? I am thinking of using these to send the otuput of a mixer on a lecturn to the amp room.

[david.elsbury]

Haven't used them yet (Christmas break and all that) but I'm sure they will be fine. Have used single versions no problem.

 

Regarding pics of the insides.... heh... They are not very pretty as I had to butcher the ethercons to fit... will put something up later today

[david.elsbury]

http://I.imgur.com/aZnr9hP.jpg

Just realised I never posted the guts. I never said they would be pretty! ;)