Guest : .... but for the termination, ALWAYS solder. *I can't stress it enough. Crimps are good, but a solder connection will stop air from reaching the contact point or the wire. *No air, nothing to make oxides with (corrosion).
To deal with the emi interference, all you need is a good shield. *Grounded foil shields are quite common in the telecom industry (the cables have a special ground cable on each end that attaches to a ground lug on the equipment on each end. Some new ones have special jacks and cable connectors so there is no need to run a wire to a ground lug, also gives a better ground). *Trust me, when you have 1200 phone lines in 2 square feet of equipment face, emi interference is the highest priority. *If it's good enough for them, it's definately good enough for us.
A couple of points.
A proper crimp is a cold weld, it is by definition, air tight. Unless actual liquids entire the area of the crimp, and corode fro the edges of the crimp in, then it will do no worse than a solder joint. I wil note that by the time this becomes an issue for a proper crimp, that the solder joint will also be corroded.
Second, equating the phone line requirements to audio is not exactly kosher. Limited bandwidth signals with a limited dynamic range, with specialized grounding practice does not mean that a simple foil shield will suffice for analog audio use.
Besides, I guess you have never heard other folks talking in the background on a long distance line before.
With crimps, yes a good crimp should be air tight, but even with the proper crimp dies (and I also suspect most people buy one of those crimper/stripper/cutter abominations that really don't work all too well), I have always seen some form of oxidation of the conductor upon loosening the crimped connector and slioding the wire out. I feel its better to have any kind of oxidation outside of the joint, and not inside. That is why I prefer to solder the joints.
Also note that air molecules are far smaller than evporated water molecules, which are in turn smaller than normal water molecules. If water can get in, so can air.
Given though, this point seems to have followers on both ends, and is about as religious to some as the whole burn-in debate is for some.
About telco apps.
When I was talking about telco apps, I was talking about T-1 lines in particular, not POTS. POTS lines vary widely in quality from region to region. POTS stands for Plain Old Telephone Service, and is used to discern from it and analog trunk lines, digital trunks, fiber, etc.
T-1 lines have a higher standard for signal quality and reliability. Also T-1 equipment tend to be very high density. Imagine a unit the size of 3 standard sized recievers with 50 T-1 lines coming out of it...thats a capacity of 1200 callers.
For POTS lines, the factors that can cause your crosstalk issue is quite complicated, but the major factors are the premise wiring on both ends, the switching systems used through the entire route of your call, and the presence of a PBX on either end. Some PBXs don't play well with certain switching equipment/other PBXs...which leads to a very noticable echo.
In cross-country calls crosstalk is very common, and can at most times be narowed down to switching equipment differences. See in europe they use a different telephony standard than us, and the general signal parameters are quite different. I am not sure about what switching systems are used in the other continents however.
Also in many rural areas the lines and switching equipment are generaly ignored until a good number of service complaints are filed. So it's not too uncommon to find crossbar swithes still in use (which are notorious for crosstalk).
If you are so bothered by foil shields, european spec for telehony cable EMI grounds is a 9th wire in the cable that is only fou grounding purposes. Some hardware makers here in the states choose to use it on their gear though. Mostly in order to make their gear pass FCC testing.
Either way, if adding extra EMI grounding makes you feel good, go for it. I just feel that the return would be negligible. I do not have the money to go to FCC labs to verify however. Maybe we can take to the EMI dicussion to another thread sometime.
well, take care man. It's been good chatting.
Now can someone actually name these exotic cable companies? Where is the data that proves theses cables aren't all they claims to be.
I'm new to this HT thing but not internet forums so I'm not bent cause I think my cable are getting flamed, I just need to get edumacated
The proof is in the pudding. Here you go.
Speaker Cable Face Off
There will be many others to follow as we are just beginning
Pursuing the truth in audio & video...