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Hi, I'm currently wiring up a couple of panels for a wall in a studio sound booth. The panels are already loaded with female XLR and female horizontal TRS jacks. I would like to designate one of the 1/4" TRS jacks for an amplifier to speaker cabinet connection.
Can I use one of these existing female 1/4" TRS jacks for a speaker connection if I wire it with two conductor stranded 16 awg? Or will I need to replace the jack specifically with a speaker 1/4" jack?
The remaining jacks will be wired with shielded three conductor 22 awg.
Thanks.

Comments

Boswell Sat, 03/27/2021 - 02:13

PO jacks are sometimes used for speaker connections, but there are several things to take into account:

a) what power level you are expecting to put through the speaker connection
b) how much speaker plugging and unplugging you expect to happen
c) whether the sleeve of the speaker jack can be isolated from the metal panel and all the other connectors on it
d) what the danger is of a microphone or other signal source being mistakenly plugged into the speaker jack
e) whether there is physical room on the panel to replace the jack with a Speakon or a 2-pin power XLR connector
d) whether the loudspeaker drive amplifier output can tolerate short circuiting if the jack is unplugged when in use

So, several things to ponder. BTW, I'm not sure exactly what you mean by a "speaker 1/4" jack".

paulears Sat, 03/27/2021 - 02:14

I have very few rules but the one I do have is NEVER put a speaker connection on a jack. Electrically the jacks will be fine but even if you take great care, somebody else might not and you end up sticking volts into devices expecting milliVolts. If you have to do it and we’re talking lower power, thinner cable is not an issue. My studio monitors are running on balanced mic cable that was spare in the duct.

Fatalmasterpiece Sat, 03/27/2021 - 02:21

Boswell, post: 468332, member: 29034 wrote:
PO jacks are sometimes used for speaker connections, but there are several things to take into account:

a) what power level you are expecting to put through the speaker connection
b) how much speaker plugging and unplugging you expect to happen
c) whether the sleeve of the speaker jack can be isolated from the metal panel and all the other connectors on it
d) what the danger is of a microphone or other signal source being mistakenly plugged into the speaker jack
e) whether there is physical room on the panel to replace the jack with a Speakon or a 2-pin power XLR connector
d) whether the loudspeaker drive amplifier output can tolerate short circuiting if the jack is unplugged when in use

So, several things to ponder. BTW, I'm not sure exactly what you mean by a "speaker 1/4" jack".

Good point about isolation.
I want to be able to have a 100w tube amp head in the control booth routed through the panel to a 4x10 speaker cabinet in the sound booth to record the cabinet with microphones. Probably won't be plugging and unplugging much but this studio is in my own house so there is very little chance anyone else is going to mess with it. There is room for a speakon, just wasn't sure if it was really necessary.

Can I get away with these that are installed:
https://www.parts-express.com/Rean-NYS212-1-4-Stereo-Jack-Switched-092-118
Do I instead need one of these (or a speakon)?:
https://www.parts-express.com/Switchcraft-Z15J-1-4-High-Power-Speaker-Jack-093-1056

paulears, post: 468334, member: 47782 wrote:
There used to be some dedicated jacks for speakers with stronger springiness to try to stop the damn things falling out. Fir me speakers are only ever speakons. Jacks were never a good connector for hundreds of Watts and higher voltages.

+1 to speakon recommendation but thought I could get around it and just use existing plug.

Boswell Sat, 03/27/2021 - 02:30

OK, perhaps you should have mentioned the context in the first post!

Tube amps can be very sensitive about even momentary shorts and opens in their outputs. I would say that you must replace the jack you want to use for the speaker connection with a locking, non-shorting plug that is incompatible with any other connector in the panel.

dvdhawk Sat, 03/27/2021 - 08:34

Hello, and welcome.

Of course you are free to do as you wish, but 1/4" connectors are (and have always been) a terrible way to transfer any significant power. In addition to the momentary shorting that occurs (which is a tube killer), consider how tiny the point of contact is when you press a flat bar against the radius of a cylindrical surface. *see illustrations

If you have the tools to punch / drill / ream out the hole to fit a SpeakOn in there you'll get a vastly better connection. There is much more surface area in the contacts of the SpeakOns to accommodate the high amperage speaker level. And they are designed to make contact with the (-) before the (+), which is ideal. They lock in place and are easily repairable, soldering optional. What's not to like?

Guitar players are notorious for trying to squeeze every bit of tone they can out of their rig, but will then shoot themselves in the foot with crappy connections where the real power is.

I know, I know... it was good enough for Leo, and Jim, and Randall, and the rest, but there are better options now.

Best of luck!

Attached files

Fatalmasterpiece Sat, 03/27/2021 - 12:15

Boswell, post: 468336, member: 29034 wrote:
OK, perhaps you should have mentioned the context in the first post!

Tube amps can be very sensitive about even momentary shorts and opens in their outputs. I would say that you must replace the jack you want to use for the speaker connection with a locking, non-shorting plug that is incompatible with any other connector in the panel.

Seems like a good idea ultimately :)

dvdhawk, post: 468340, member: 36047 wrote:
Hello, and welcome.

Of course you are free to do as you wish, but 1/4" connectors are (and have always been) a terrible way to transfer any significant power. In addition to the momentary shorting that occurs (which is a tube killer), consider how tiny the point of contact is when you press a flat bar against the radius of a cylindrical surface. *see illustrations

If you have the tools to punch / drill / ream out the hole to fit a SpeakOn in there you'll get a vastly better connection. There is much more surface area in the contacts of the SpeakOns to accommodate the high amperage speaker level. And they are designed to make contact with the (-) before the (+), which is ideal. They lock in place and are easily repairable, soldering optional. What's not to like?

Guitar players are notorious for trying to squeeze every bit of tone they can out of their rig, but will then shoot themselves in the foot with crappy connections where the real power is.

I know, I know... it was good enough for Leo, and Jim, and Randall, and the rest, but there are better options now.

Best of luck!

The only reason I thought of it is that both the speaker cabinet and amp head only have 1/4" connectors so having the passthrough be the strongest link didn't seem necessary but it certainly can't hurt!

paulears Sun, 03/28/2021 - 01:17

There can also be instability when you could have 80v on one socket and .8v on the one next door. To be honest I’m be never actually had this but anecdotally others have. Even in your own house I bet you’ve plugged in a jack to the wrong socket? I’ve plugged a keyboard sustain pedal into an audio out plenty of times

Boswell Sun, 03/28/2021 - 04:45

Fatalmasterpiece, post: 468343, member: 52557 wrote:
The only reason I thought of it is that both the speaker cabinet and amp head only have 1/4" connectors so having the passthrough be the strongest link didn't seem necessary but it certainly can't hurt!

There is little possibility of confusion on the connection panels of an amplifier or the back of a speaker cabinet. Keeping the various signals distinct and avoiding the possibility of mis-connection is paramount on a multi-signal connection panel.

paulears Sun, 03/28/2021 - 06:31

The convenience of connectors is always balanced against the chances of damage. I know one theatre that have loads of panels all over the building with a big 2 bay patch in the plant room - so anything can be patched to anything for speed and convenience. A typical panel has ¼" 3 circuit jacks, 3,4 and 5 Pin XLR and BNC and VGA socketry. Most work - some are tricky. The XLR 5 pin, for example. It was thought that it was best to wire all pins, as likely users would be for the lighting folk, but then somebody pointed out that some lighting desks use two universes of DMX on one connector - so universe 1 would be on pins 2 and 3, with universe 2 on pins 4 and 5. The sound department liked this idea because with the same Y splitter, it gave them a stereo mic ability up in the roof. It worked well enough - but the lights people used gender changers very often when feeds and destinations reversed - so occasionally you'd get the nasty noise of a DMX lighting controller going into a sound input. The 4 pin XLRs were for scrollers - DMX on two pins and power for the scroller motors on the other two. What kind of connector does the British most popular intercom headset use? Yep - 4 pin XLR. It's bad enough with the mainly Chinese tendency to use 3 pin XLR on lighting kit that confuses.

We now have speakon, powercon and others using very similar designs and despite not supposing to mate - you see quite a few loudspeakers with very worn and loose speakons - I wonder what kind of plug people managed to force in that did the damage? Seeing a cable hanging from the fly rail in a theatre with a 3 pin XLR is not simple at all - it could be to connect to a mic, or a light - or even in some places loudspeakers, as plenty from the older day (like Turbosound) used 3 pin XLR connectors for their speakers. The absolute worst and a real killer is a Chinese made smoke machine that uses a 3 pin standard XLR connector. The mains voltage on one pin is simply connected to the other at the remote end. That's what looks like an audio cable laying on the floor with 240V on one of the pins. In the UK, these have a name - Widow Maker.

Even the humble BNC is not foolproof. It's for video monitors right? 75 Ohm 1v p-p video? Unless it's being used to get the radio mic receive antennas down from the fly gallery rail to the receiver rack - 10m of the wrong cable impedance is made up for by the extra height - and it'll carry power to power an antenna that needs superimposed DC? Of course it could also be carrying 25W of RF from the local area repeater for all the walkie talkies. TV monitors don't like that very much.

Let's not even go down the grey vs blue powercon route - one for input one for output, but many people not knowing which is which and you should only ever find a mains connector wired to a blue powercon. Trouble is I see quite a few laying around where it's mains connector to a white one. Which of course works fine on a light with in and out - and the usual blue-white patch lead also works fine. Until you get to the other end and a helpful stage crew person sees a dangling blue connector and an empty blue one on the light. In the UK, we have three phase electricity in theatres and events venues. The phase to neutral voltage is 240V 50Hz. Phase to phase is 415V. Lowest current connectors are 16A. plugging that dangling cable in can be spectacular. Quite how many lights in the chain will die is a very good question. Plugging that cable in at the top of a ladder might bring the ground into contact very quickly. Mixing the uses in a panel is the danger, not really the connector. It is what they are carrying that matters.

pcrecord Mon, 03/29/2021 - 05:39

There is some specially made 1/4 inch plugs made for speakers if you don't want to modify the amp and/or the cabinet. Then to go through the wall, speakon connectors are the best and safest way to go for amplified signals.
you can have it mounted on a wall box for switches.
Also I would go up to 14 gage wire to be safe.
 
 

Attached files

paulears Mon, 03/29/2021 - 11:29

I actually looked up the American Wire Gauge thing, and found some surprises? Two-core speaker cable in the UK for light duty, lower power is usually about your 15.5 gauge - our 1.5mm2 but our stage cable and the kind of cable feeding higher power speakers is usually 2.5mm2 your 13 gauge being closest. The 4 core 2.5mm2 is the common cable used by people who biamp, and just fits in a speakon.

dvdhawk Mon, 03/29/2021 - 12:40

That's true, Paul. 13AWG wire fits nicely. Assuming you're using a good quality, high-strand 12AWG wire you're likely going to have to snip a few strands to fit it in a SpeakOn connector. I used to use 10AWG on sub cabinets, but they were old Hubbell connectors the size of a soup can.

I use some 2 conductor and 4 conductor speaker cables in my PA rig. They're mostly 12AWG, but I do have a few 13AWG and even a couple 11AWG which feed little 2-way breakout boxes

The OP only needs to concern himself with 2-conductors, which couldn't be easier, but using 4 conductor cable with SpeakOn connectors on each end is a bit of a headache. I suppose it's the tradeoff for the convenience of using cables with the same gender on each end. The orientation of the conductors remains the same throughout the length of the wire, the pinout on the SpeakOn obviously doesn't change - so when you arrange the wire colors to Pins (1+) (1-) (2+) and (2-) to the correct layout on the first end you have to physically cross conductors over to match the reversed SpeakOn for the other end of the cable.

It's always something...