My Headphones Always Go Out?

I dunno about you, but headbanger types go through 'phones like crap through a goose! :-) It's called "metal fatigue" - just like bending a paper clip back and forth a bunch of times, the little wires become "work hardened" which makes them brittle and pretty soon the wire will break, often at the slightest tug. Some manufacturers use a special ultra-flexible conductor that resembles a very fine metal tape that is wrapped around a strong insulating fiber that provides strain relief. The wrapped nature of the conductors allows them to flex a lot more than conventional stranded wire. The trick is to find which ones have that kind of conductor; they will most likely be more expensive, but do not go by price w/o knowing for sure if they are the ones I am referring to. Sorry, I do not know which ones are manufactured like that - I generally repair my own broken headphone wires, and the ones that I mentioned above are much harder to repair via soldering.

1. Are there any restrictions on using crimped connections to electrical devices (receptacles, switches)?

No code problems as long as they are sized to maintain an acceptable cross/surface area. Which translates into use the right size and you are good to go.Yellow are 10-12 gauge -- only one wire per connector -- the hole or opening in the crimp is a match for the screw or bolt -- use the correct tool -- and crimp into the split in the wire cupThey do come with the seam brazed, they are a big step up in quality and finish. There are also little copper barrels, like a wire nut without the plastic part, and crimp instead of spring. These are the correct part to use when trying to get a stranded wire under something like a load center neutral screw bar.Completely personal opinion, on wire terminals and associated parts. I do not use the generic wire terminals with the plastic 'strain relief' covering, like those shown. The plastic in these things is not engineered to crush,'just right. ' If I wind up in a situation where they are all I have, I pull the plastic off of them and use them without. This also allows me to see if the wire insulation jacket really meets the edge of the connector, to make sure all of the wire strands made it inside the barrel of the connector, and to check and see if or how much the seam opened.Heat shrink after, if it will help with strain relief, or just look nice, is the way I finish them. The right tool, the 12 in 1 tools sold right next to the terminals, are just not good (except for the screw cutter in the Greenlee brand one, thing works great, I carry one for just that reason.)The Klein 1006 is the best generic terminal crimp tool of its kind. It 'feels right', it has good weight, it is not stamped sheet steel, the crimp forming nests are supported and sized well, and under $30 on the home depot web page. If you must use insulated terminals, and there are valid situations for it. The Klein 1005 is made to crimp both insulated and non-insulated connectors.Wire Strippers, I know real men use linesman's pliers for almost everything, but sometimes, they are just not the right tool. Klein 11049 are designed for Stranded Wire 8 to 16 gauge. You have no idea how wonderful the difference vs. using strippers for solid wires. They have 4 pair in this series big and small in both stranded and solid.

2. Macbooks (used OK) for around 600-700?

I would never buy a used computer - especially a laptop. There are too many risk factors. What did the person use it for? Travelling around? Checked as luggage? Was it overclocked? Dropped? (Even if there are no physical signs of damage). Dropped repeatedly? (No way of knowing). Used for some illegal purpose? (i.e. child porn, hacking, etc.) And like you said - there are a million scammers out there. Considering that you can get an entry level Macbook pro brand new for around $1200 (with a warranty - and up to date O/S), I do not think it would be worth the headache. The higher end macbooks do have flash-based hard drives which are cool, as well as bigger displays (which means a bigger case), but the main thing I like about macbooks is the aluminum case, and the magnetic power supply (I literally worship at the feet of the genius who came up with that one - almost every piece of electronic equipment I've ever owned has managed to screw up because of crappy power input/lack of strain relief). I also like that they use Intel processors now - the first thing I would do is either wipe the Mac o/s, or dual boot - and put windows XP on it. Nothing against mac, it's just that 99% of the software I use is not available for macs (or is hard to find/expensive to buy). I did just get an external soundcard/preamp that came with a set of recording software for both pc and mac though - so I've been pondering setting up the old Mac G3 workstation that is currently sitting in my garage unused. I am going to keep using the 22" Sony trinitron monitor with it too! That thing is a beast!