How do amplifiers work?

[DJItalianICE 10+ year member]

I busted out a voltmeter and tested the sub output and it was eitehr 40v or under, but it jumped a lot. I'm guessing that voltage controls how hard the sub hits (movement). Are amps constant or do they fluctuate and/or remain proportional somehow to the voltage? J/W

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[cjjackson85 5,000+ posts]

Yes they do...

 

[Raven 10+ year member]

Voltage sent out to a sub is directly related to how much the sub is supposed to be putting out, acoustically. Example, during a bass hit or playing a sine wave, you'll get a higher voltage than just music. An amp basically just turns 12v DC into AC current that conforms to an input AC current, only at a significantly higher voltage.

http://www.bcae1.com

 

[DJItalianICE 10+ year member]

Voltage sent out to a sub is directly related to how much the sub is supposed to be putting out, acoustically. Example, during a bass hit or playing a sine wave, you'll get a higher voltage than just music. An amp basically just turns 12v DC into AC current that conforms to an input AC current, only at a significantly higher voltage.
http://www.bcae1.com

so wait

is amperage then constant? Or Amperage is directly proportional to the volume control and voltage is regulated by spikes in music?

 

[JimJ 5,000+ posts]

Amperage is related through voltage through Ohm's Law...

An amp basically just turns 12v DC into AC current that conforms to an input AC current, only at a significantly higher voltage.

You could write entire books on the subject, but when it all boils down to it, that's what an amplifier does, no matter what the design of it is.

 

[thch 10+ year member]

how amps work...

DC input to Switchmode power supply.

SMPS converts the 12V DC into a high voltage complex AC signal.

supply filtering converts complex AC signal into two higher then 12V DC signals

actual amplifier circuitry converts the two higher voltage DC signals into an AC signal that resembels the input signal on the RCA, just with hgiher voltage (higher voltage implies higher current).

so its a DC - AC - DC - AC conversion.

DJItalian. in a _good_ amplifier, current (amperage) is independent on the voltage. the amp sets the output voltage, say moving the output voltage between +-20V and provides as much current is needed to make this happen. because energy is stored/released in the speaker, you could get cases where the amplifier has a positive output voltage and yet a negative output current (the speaker is providing power to the amp which is converting said power to heat). the main point is that the amp merely changes the output voltages and provides any amount of output current*.

*real amps have limits on output current.

 

[JimJ 5,000+ posts]

That's a pretty good explanation. 120VAC solid-state amps only differ in their input power supply, but the rest of it is the same //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Even tube gear functions fundamentally the same way, only they use massive transformers to step up the input AC to the rectifier and couple the active devices to the speakers, because the output impedance is so much different. But electrically, it's the same thing happening.