Amplifiers: High Current? High Voltage?


I've seen alot of mention about current-based and voltage-based amplifiers, and I am confused. I thought all amplifiers recreated the wave form by varying voltage, and their interaction with the speaker (and the impedence characteristics between the two) dictate what current is drawn. I understand that the power supply of some amplifiers is less current restricted than others, but my (current) understanding also says that all amplifiers work by controlling voltage. Is there really such a thing as an amplifier that controls current rather than voltage?
peter_s
Thanks Herman. That's what I was getting at with my question about capacitors. I assume all prior discussion about transformers has been input transformers.
the law is current times voltage equals power. in the case of speakers, all a voice coil is, is an inductor used as a motor. for inductors, the larger the current, the stronger the magnectic field. voltage isn't really that important when it comes to pushing a speakers. the higher the current, the more powerfull the electromagnetic field is. high voltage has its advantage, it saves a lot of power, but for subwoofers, high current wins hands down. when looking at amplifier specs, people don't know what to look for, power equals watts, but peak doesn't equal rms, the difference between regular amplifiers and high current amplifiers, is that, regular amplifiers us more voltage in the equation then current (which is like 50volts times 2amps= 100watts when you could use 10volts times 10amps to get the same power but create a stronger magnetic feild), when it is current that is pushing the relitive motion of the induction (voice coil). but another thing is, voltage is what pushes your current through, and with out that voltage, no current would flow, voltage in equals voltage out, and all voltage is, is electronic pressure.
the difference between regular amplifiers and high current amplifiers, is that, regular amplifiers us more voltage in the equation then current (which is like 50volts times 2amps= 100watts when you could use 10volts times 10amps to get the same power

"Regular" amplifiers don't use more voltage in the equation. All voltage amplifiers, which is what almost all amps are, whether or not they are capable of producing high currents , try to maintain a constant voltage out for a given voltage in. The amount of current that flows will be the voltage divided by the impedance, and the impedance is whatever it is. So called "high current" amps are the ones that have the ability to deliver more current if the impedance dips real low, but don't somehow magically push more current through the speaker than one with less reserves.

Another simple way to look at it to compare a much of AA batteries connected in series to get 12V and compare that to a car 12V battery. Both will put out 12V but the AA doesn't have much current capacity.