I now have to say the Speakon system is closer to 99.99% foolproof. After making about 10000 connections give or take over the last 20 years, I finally had a problem last night. My signal started cutting out on the gig. Moving the speaker wire around seemed to affect it. I thought I had it positioned okay, made it through one song, then we started another one and: silence. Grrrr... At first I thought it was the top plug but it turned out to probably be the bottom. I finally found a position that got me through the set with no more interruptions. During the break, I checked the connections. One set screw was just slightly loose. (The screwdriver tip on my Swiss Army knife can opener worked in a pinch.) I put it all back together and everything was fine. Speakon is without a doubt the best connection method in my book, but: lesson learned. I am going to start checking those set screws periodically, and keep my spares & tools more handy.
Periodic maintenance is important. Screws can loosen. Never seen them tighten with time. Interesting physics behind screws. An engineer at Neutrik told me that oxidation occurs on contacts and it can be cleaned. I find that Neutrik Speakon connectors can go for many years without the need for cleaning.
NO electronics of any sort are ever 100% foolproof. That's why taking good care of them (keeping them clean, not abusing them, not leaving them out in direct sunlight for long periods, not exposing them to temperature extremes/fast temperature changes, etc.), preventative maintenance, and having backups are all important.
Phew - for a sec I thought maybe I was supposed to have been tinning the wires! If it makes the set screw connection more brittle therefore unreliable, I'm very happy to continue not doing it.
Don't tin them. Neutrik says that specifically. Any screw terminal can loosen over time -- they need an occasional inspection and retightening. IME, the screw terminals on shop-built electrical items, like the ubiquitous "quad box" are the most likely to loosen with use. @beans-on-toast is right -- nothing seems to tighten over time. When I was operating a PA company, the slow period of January and February was the time to go through all that kind of stuff and tighten things up. Almost inevitably, some alarmingly loose screw terminals would be found.
Do not tin stranded conductor in this application. The design is intended to clamp / splay / deform the bundle. Use Pozidriv for securing the connections. Riis
Nope, don't tin them No, do not tin. Tinning allows the connection to cold flow under the screw pressure causing them to loosen. Nope, don't tin them
Why you should not tin twisted stranded wires that are going into a screw terminal or a crimp connector. When you solder a stranded wire, you have a blob of wire between strands. The problem is, when the speakon terminal is tightened, pressure is applied. The solder under pressure deforms and eventually moves. This is called creep and spaces between wire strands and a loose connection results. More details below. Creep (deformation) - Wikipedia
Learn something new every day. Now I'm wondering if I should take the cables I made apart, cut off the tinned ends, strip them, and reconnect.
No, I wouldn't bother. Open them up, inspect and retighten them every year or so. When you replace them, you can correct your mistake. But otherwise, I wouldn't worry about it too much.
I've understood this to be what they called cold flow — where solder, under pressure in a screwed terminal, tends to give way and can cause play as it flows, in time, out of the terminal. Where there's a screwed termination there's no need for anything other than the wire and the fastener. I'll always twist the wire and double it over if the terminal allows it — even solid wire gets doubled over and twisted before it goes in, if the terminal allows. Good idea not to scrimp on plugs either. Neutrik all the way Don't trust the others.
If you’re using an amp with tubes in the power stage with speakons, I would redo the connections. Otherwise you risk an open connection which could damage the amp. It’s the same as turning on the amp without a speaker cabinet connected.