This is a place where a lot of the discussion will center around power. It may be in the form of balanced 220/240VAC step down balanced transformers or it could be in the form of 3.3VDC inside of a computer. Stop and think:
(An aside. I always get a kick out of that phrase - "stop and think." What if you never started again?)
Back to the topic: What does electricity do? It powers our lives, lights our world, makes everything MUCH easier. It also eliminates crazed murderers and other dregs of humanity in an awful display of searing, smoking finality. It is absolutely imperative that we approach electricity with an almost religious reverence and fear, or at least a healthy respect. In short, doing anything stupid can get you killed. We don't want that.
When working around AC power in particular, safety precautions must be taken. Make sure that you are absolutely comfortable in taking your life in your own hands before starting and project that deals with powerline level voltage. Do all of the standard things: make sure appropriate circuit breakers and/or switches are in the OFF position; TEST THOSE CIRCUITS to make sure they are off; make sure that storage circuits are properly and completely discharged; wear insulating gloves if at all possible; wear rubber soled shoes; use caution at all times and
think about what you are doing. The thing that injures or kills most weekend warriors is simple inattention or being distracted. The best place to start is to make sure that every circuit in your home is properly wired. Your friend is a simple circuit tester available at any Lowes, Menards, Home Depot or my favorite place for these things - Harbor Freight. I now include a Harbor Freight circuit tester with all of my power products.
http://www.harborfreight.com/electric-receptacle-tester-32906.htmlor
http://www.harborfreight.com/electrical-receptacle-tester-with-gfci-diagnosis-32907.htmlA special note about DC power: just because it is 12VDC don't think that you are in the safety zone.
My Dad was a lifelong electrician that worked everything from house current to 77KV. He had an exemplary service record and was an apprentice's dream to train under. He never got rattled and always stressed safety as THE most important aspect of an electrician's job. One day Dad and I were working on my '57 Chevy (sigh) and we were trying to track down an under-dash rattle. I was pounding on the top of the dash and Dad reached under the dash to put his hand around a bundle of wire to see if the rattle was related to that bundle. The key was off. Instantly, I smelled burned flesh as his gold wedding ring completed a circuit somewhere under the dash. His injuries were such that he almost lost his finger from the ring becoming a glowing circle of pain and he had a deep gash close to the radial artery in his wrist from trying to tear the dash out of the car as he yanked his arm out of that closed space.
A 12V battery can wreak your day in a heartbeat. You ain't lived until you see one short. It can be a 1AH or a 100AH like I have for my system. A battery is an instantaneous source of pain for those that are inattentive or ignorant. Be extremely careful when working around DC, especially because we tend to think of it as safe. A direct short is to be avoided at all costs. Always disconnect the battery's cables and it is a good idea to put an insulating sleeve around the positive (+) terminal. A battery can turn a screwdriver into a branding iron in an instant and most batteries don't have circuit breaker protection. Consider yourself warned.
Vacuum tube gear: so much has been written about tube safety that I'll just refer you to here:
http://www.aikenamps.com/SafetyTips.htmlAlmost everything Randall discusses here is a demonstration of common sense. READ IT!!!
The bottom line here is that if you are not experienced, comfortable with or are leery of working with something that can kill you, hire a trained and competent professional. I heartily recommend that you check with friends or Angie's List to find a good one. There are a lot of charlatans in the trades, especially now that the economy has tanked. Electricians and plumbers - everyone needs to know at least one good one.
I don't mean to scare anyone off of what can be a place (power) where it is possible to reap huge improvements in SQ for your system. It is simply that one must have a healthy respect for what you are doing and pay attention. When I was in the semiconductor industry I was a line technician on high energy ion implanters. When people asked what I did for a living I told explained that I worked on a death ray. Imagine, if you will, a tool the size of a single car garage that has these attributes: vacuums to the -8 torr; high energy ion beam generators and accellerators; ionizing radiation; intense magnetic fields; poisonous gasses and solids; cryogenic temperatures; source currents of ~250A; voltages to 500KV and total energy in the 1-2Meg electron volt range. Best of all? We wore conductive soled shoes in the FAB for static dissappation. I simply paid attention and was good at what I was doing.
Let's make a pact: ask if you don't know, OK?
Have a safe and fun time in your journey.
Dave
