Speak-On cable users

[bclaire]

A warning for anyone who connects their gear using Speak-On cables. The Neutrik connectors on the ends use set screws to attach to the wires and can loosen. On a tube amp, this could prove disastrous. I had some issues with my cables for my PA, and went through all of my cables and connectors last week. Out of 7 cables, I found five connectors with loose set-screws. Two of them had stopped working altogether... once retightened, they were fine.

So my advice is, if you use them, CAREFULLY take them apart so you can tighten the set screws. I say carefully because I unscrewed one and the wires came right out and I had to figure out which two of the four set screws the wires went to!

[a.hun]

Yeah I wired up a Neutrik speakon for the first time a few weeks ago. (New bass cab.) Discovered the same - screws to hold the wires fast. Not really a problem though. Heres the trick...

What I did (and do when wiring mains plugs with similar screws to fasten the wires) is to twist the cable ends so the wire strands are in a loose spiral. Then you tin it with solder so the solder flows right through and between the twisted wires. Then when it cools and you screw the cable ends into the connector they don't splay out but stay as one mass which will just squash a bit. That stops them slipping out. Of course you want the screws pretty tight but I found I could put a surprising amount of torque on those tiny Neutrik Speakon screws - plenty to hold the cable fast.


Andy.

[Randy Bass]

That's a nifty "New-trick" for Speakons, Andy. Thanks for the tip!

[bclaire]

I'm thinking maybe soldering the wires directly to the posts...

[bgarrett_uk]

It's good practice to solder all wires on the power side. I have speakons on the PA amps - wires will work loose over time and Andy suggestion is good, screwing in the screws the screws too tight on untinned wires can sever them accidentally.

Soldering into the receptors is the best solution then put the screws back in.
Cheers
Brian

[TheOrangeJuicer]

I don't know about all of that guys. For one thing, making a set screw connection on bare wire is very sound. It's the best electrical connection that can be made short of "cold welding". The screws need to be tight though. That may mean getting a proper fitting screwdriver, which might prove a challenge in itself. The only issue with the screw setting is that a lot of use can cause them to come loose.

Not all Neutrik connectors use the set screw method. I have some that have solder connections. You can also solder the nearest ends after the farthest has been inserted and tightened securely with the set screw for added stability. Even a solder joint can and will break eventually if the connection is moved. the best way to prevent movement is to ensure that the connector is solidly connected to the cable jacket at its strain relief connection. If it's loose there, it'll work on the electrical connections continually until they fail.

You can tin the wires and then use the set screws but it'll not compress the wire as much, not make quite as good an electrical connection, and it'll still work loose under the same conditions. In fact, it should come loose sooner, if the set screws were properly tightened on the bare copper in the first place.

My guess is that the set screws were not as tight as they should have been because of the right tool not being available. That if coupled with a poor strain relief connection simply will not prove "road worthy".

[a.hun]

I don't know about all of that guys. For one thing, making a set screw connection on bare wire is very sound. It's the best electrical connection that can be made short of "cold welding". The screws need to be tight though. That may mean getting a proper fitting screwdriver, which might prove a challenge in itself. The only issue with the screw setting is that a lot of use can cause them to come loose.

Not all Neutrik connectors use the set screw method. I have some that have solder connections. You can also solder the nearest ends after the farthest has been inserted and tightened securely with the set screw for added stability. Even a solder joint can and will break eventually if the connection is moved. the best way to prevent movement is to ensure that the connector is solidly connected to the cable jacket at its strain relief connection. If it's loose there, it'll work on the electrical connections continually until they fail.

You can tin the wires and then use the set screws but it'll not compress the wire as much, not make quite as good an electrical connection, and it'll still work loose under the same conditions. In fact, it should come loose sooner, if the set screws were properly tightened on the bare copper in the first place.

My guess is that the set screws were not as tight as they should have been because of the right tool not being available. That if coupled with a poor strain relief connection simply will not prove "road worthy".

That'd be my guess too. The overall outer cable diameter has to be in the right range for the strain relief to grip it firmly. That being the case firmly tightening the internal screws and the cable strain relief clamp should eliminate any movement.

Sure, even well soldered joints need to be held firm without movement or the joint will fail eventually. Did consider just screw fixing the bare wires with these speakons. Not sure if having the solder tinning would make for a significantly poorer electrical connection than the pure copper wire. (As in I really don't know!) I've never worried about the electrical resistance of the solder at any rate, and don't imagine it should be a real problem, so I'm not that worried right now. But now I am intrigued...

[Coffee pause]Zing![/Coffee pause]


Okay... Just opened things up again and I see that Neutrik have neat little movable and bendable metal plates which each screw actually compresses against the wire. Neat!

Have to agree Bill. I see no problem at all with just using the bare wires. You can tighten the screws very firmly (with the right driver) which will just crush the wires and certainly not guillotine them. With the strain relief clamp also tightened properly on the cable that looks pretty secure to me.


Andy.

[bclaire]

Here's the problem: while the connector has stiffening properties to it and the cable itself is held firm, just by transporting and setting up/ tearing down the set screws loosen on their own. I'm referring to doing acoustic gigs, say 4-5 times a month and then setting the PA back up in my basement. Not exactly a lot of usage, and I would have to say, within 6-8 months I have had to open up and tighten set screws on a number of connections. I have a zillion screwdrivers, and have exactly the right size screwdriver for those little Phillips' head screws.

For my Crown PA heads, it hasn't been much of a worry save the loss of sound quality, but if it was a tube bass amp, it could be very costly if the output tranny failed!

I think I'm going to recheck my main cables after a couple of months and see what's going on there... if I find lossening again, I'm going to hard solder the wire to the surround and then tighten up...

[TheOrangeJuicer]

...Not sure if having the solder tinning would make for a significantly poorer electrical connection than the pure copper wire. (As in I really don't know!) I've never worried about the electrical resistance of the solder at any rate, and don't imagine it should be a real problem, so I'm not that worried right now. But now I am intrigued...

[Coffee pause]Zing![/Coffee pause]


...
Andy.

Solder has very poor conductivity compared to copper. Even a silver bearing solder is a poor conductor by comparison. That's mostly a technically esoteric point as in practice, you'll be challenged to hear the difference in a very low distortion set-up. In a guitar tube amp...

[a.hun]

Thanks Bill, thats reassuring. If the difference isn't obvious with your hi end audio gear than I should be okay with my bass rig.

Billy, I'd have thought the major factor would probably be actual cab vibrations in use. After all most cabs with speakon connectors are higher powered so there will be quite a lot of vibration. I'm quite used to routinely retightening combo cab screws and bolts once in a while as they can definitely loosen off in use. (Reason why a few high end makers eg Bad Cat actually use locking nuts throughout!)

Like you I'm going to keep an eye on my bass cab cables to be on the safe side. Certainly don't want to fry my Hiwatt or Orange amps OT...

Thanks for the heads up anyway!


Andy.