Post by dbster on Dec 12, 2011 7:03:16 GMT -5
In the accessories section of this forum there was a discussion of speaker wire. So this may be just too newbie, but in the American Wire Gauge system, the larger the wire, the smaller the gauge number. The 15 amp circuits in your house's electrical wiring are done in 14 gauge, the 20 amp circuits in 12 gauge, and the 30 amp circuits in 10 gauge.
However, if you very simplistically apply Ohms law here, power = current squared times resistance, so a 300 watt, 4 ohm speaker would draw no more than 9 amps (9^2 * 4 ~ 300). Tech warning: I am an EE so I know this is way simplified, but I think OK for this section.
Now, I am not going to discuss cable merits or value, but I will mention a few facts:
1) The higher the frequency the more 'skin effect', i.e. the electrons travel more along the surface of the conductor. So for DC in your car or 60 Hertz in your power wiring, this effect is negligible. For higher audio frequencies, maybe. This would tend to indicate that you want a larger wire than necessary just based on current
2) House wiring at your favorite hardware store is cheaper than audio speaker wire of the same gauge. But making a good connection at the amp and speaker terminals is harder with solid wire. Also, house wiring does not have fixed spacing, which is useful in controlling impedance. So if you want to buck the trend and buy speaker wire that is cheap and not made for application as speaker wire, start with 'heater cord' - black, flexible, parallel wire used to replace cords for toaster ovens, irons and such. This is usually 16 gauge, and is flexible. Flexibility derives from more strands in the wire.
3) Shielding is useful for signals, incoming and outgoing. For your component interconnects, you want to keep strong external signals out. For strong signals as in power cords and speaker wire, it seems to me it is more a case to keep those signals in.
4) The right gauge wire that is not properly terminated is going to have a higher resistance at the connection. Spade lugs properly fitted to '5 way' binding posts, or banana plus that have a screw at the other end to internally expand the banana plug in to the jack are the two common connections I believe in. If you are going to use bare wire ends into the hole on the threaded post of 5 ways binding posts, then make sure the ends are twisted so all the stands go through the hole.
This is where many newbie electricians get in to trouble after leaving the hardware store. They don't get the whole wire under the screw head on the switch or outlet they are replacing, so they end up with a higher resistance connection, which can be fatal at high current. Or they use the simple strip the wire and shove it in the quick connect hole, and don't put enough in (FYI I never use that wiring 'feature')
And, newbiest of all, speaker wire that is made of stuff not intended for speaker wire may be harder to determine which are the red and black (or + and -) connections, so you could more easily end up with speakers wired out of phase.
However, if you very simplistically apply Ohms law here, power = current squared times resistance, so a 300 watt, 4 ohm speaker would draw no more than 9 amps (9^2 * 4 ~ 300). Tech warning: I am an EE so I know this is way simplified, but I think OK for this section.
Now, I am not going to discuss cable merits or value, but I will mention a few facts:
1) The higher the frequency the more 'skin effect', i.e. the electrons travel more along the surface of the conductor. So for DC in your car or 60 Hertz in your power wiring, this effect is negligible. For higher audio frequencies, maybe. This would tend to indicate that you want a larger wire than necessary just based on current
2) House wiring at your favorite hardware store is cheaper than audio speaker wire of the same gauge. But making a good connection at the amp and speaker terminals is harder with solid wire. Also, house wiring does not have fixed spacing, which is useful in controlling impedance. So if you want to buck the trend and buy speaker wire that is cheap and not made for application as speaker wire, start with 'heater cord' - black, flexible, parallel wire used to replace cords for toaster ovens, irons and such. This is usually 16 gauge, and is flexible. Flexibility derives from more strands in the wire.
3) Shielding is useful for signals, incoming and outgoing. For your component interconnects, you want to keep strong external signals out. For strong signals as in power cords and speaker wire, it seems to me it is more a case to keep those signals in.
4) The right gauge wire that is not properly terminated is going to have a higher resistance at the connection. Spade lugs properly fitted to '5 way' binding posts, or banana plus that have a screw at the other end to internally expand the banana plug in to the jack are the two common connections I believe in. If you are going to use bare wire ends into the hole on the threaded post of 5 ways binding posts, then make sure the ends are twisted so all the stands go through the hole.
This is where many newbie electricians get in to trouble after leaving the hardware store. They don't get the whole wire under the screw head on the switch or outlet they are replacing, so they end up with a higher resistance connection, which can be fatal at high current. Or they use the simple strip the wire and shove it in the quick connect hole, and don't put enough in (FYI I never use that wiring 'feature')
And, newbiest of all, speaker wire that is made of stuff not intended for speaker wire may be harder to determine which are the red and black (or + and -) connections, so you could more easily end up with speakers wired out of phase.
