Re: How many watts is my sub getting
Hi Ryan-
Thanks for the backup on this, because I hear folks use Chuck's line of reasoning on a regular basis. A little lab experiment might convince, or not...
This is the crux of the situation and it can be demonstrated with an AC voltmeter and a current meter like the Kill-a-watt. Connect a high-impedance AC voltmeter to the output of an amplifier and put the current meter inline with the amp's power cord. Do not connect a speaker or other load. Power up the amp and note the current draw, then apply a 60Hz sine wave to the amp and turn it up until you get, say, 50 volts reading on volt meter. Look at the current meter. It should read about the same as quiescent because there is no load. There will be a slight increase in current draw due to inefficiencies of the amplifier design, but we're talking about maybe an ampere above quiescent.
Leaving the meters attached, turn down the amplifier input and connect a speaker to the terminals with the voltmeter. Bring the input signal back up until you get 50v again, and note the current meter reading. It will be much higher than the previous readings, how much so depends on the nature of the load itself.
The important thing to remember is that voltage is POTENTIAL; it is neither work being done nor the current that supplies POWER.
Have fun, good luck.
Tim Mc
