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Current Questions

More and more, I see the word “current” in audio reviews. The reviewers warn me that I’ll “need lots of current” for a given speaker but they don’t explain exactly what it is I need or how many “lots” is. I’ve looked at a few “Electronics For Dummies”-type sites but I’m still confused. A few questions:

 

—What is current?

 

—When someone writes, “These speakers need a lot of current,” what do they mean? Is sensitivity involved? Impedance?

 

—On the amplifier end, what specification measures current?

 

—Are there subjective considerations at work in that spec? The number of watts doesn’t tell me everything about loud an amplifier sounds. Does the number of [whatever measures current] similarly leave things unexplained?

 

—Everyone asks, “How many watts?” No one asks, “How much current?” Is it really so important?

paul6001
nonoise's avatar
nonoise
11,226 posts
 

falconquest's avatar
falconquest
1,108 posts
 

I can't believe no one has answered the OP's original question. What is current? To do so we need to go back to electricity 101. Forget Ohm's law for now. Think of electricity as the flow of water in a pipe. Current is like the flow of water. It is actually the flow of electrons. Voltage is the pressure that is causing that flow. Resistance is anything that restricts the flow in any way such as a restriction in the pipe or water flowing over rocks etc. If you think of an electrical circuit in terms of plumbing, it's a very good analogy.

terry9
2,354 posts
 

To determine if an amp is "high current" - ask the salesman to take off the cover. Look for:

- one or two metal boxes or toroids (transformers) - bigger is better;

- several cans (capacitors) - again, bigger is better;

- a dozen or so 1" squares with 3 whiskers or ovals (power transistors) mounted on the inside of an exterior surface - yet again, more is better.

All of these are required to make a "high current" transistor amplifier. Or you could just ask for a brand that’s famous for it, like Bryston.

twoleftears's avatar
twoleftears
5,326 posts
 

Just as well the electron flow doesn't spill out of any unused wall sockets.

terry9
2,354 posts
 

And yes, it is important. Otherwise amp could go "poof" when a few undersized power transistors are asked to handle too much power. First the amp would just sound nasty - that's a warning. Power is defined by current x voltage, that is, IV.

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