[Circle O Willis]

So i'm just starting to learn about the use/need of amps to drive headphones and what not. on a simplistic level i'm assuming the higher the impedance the more the need for an amp to drive the fones. (if this is wrong...now would be the time to set me straight)

so question: i've seen people talk about sets that can just be used without an amp and others that need them; at what impedance (roughly) does one need to start using an amp to get the full effect of the fones?

i'm sure people will have some varying opinions, but some general guidelines would be nice. thanks

 

[Melchior]

This is wrong

Impedance does not decide whether or not you need an amp for the phones to perform. It does mean you need to crank the volume knob a little more in most cases, but usually not enough to cause problems. Low impedance phones on the other hand draw more current, which if they aren't very efficient and have an impedance that varies wildly with frequency response, require an amp capable of dealing with them. That's the gist of it anyways.

 

[Circle O Willis]

thanks....anyone know of any links or anything that could help explain this whole impedance thing, use of amps, etc. anything would be appreciated.

 

[caramelsoul]

Wikipedia is your friend....

 

[Carl]

My take on it;

Normal headphones are made out of devices called "inductors" that move a diaphragm.

Inductors work by having current passed through them.

Current flow is reduced by impedence.

The effect of impedence is offset by voltage.

Headphone drivers with higher impedence need more voltage to give the same volume level.

To get the current and voltage, you need a device to supply it, called an amplifier.

All portible players, CD players, etc contain an amp in them. They need to otherwise the signal wouldn't survive the trip along the cabling.

It just tends to be the case that their internal amplification is really substandard, thus leading one to use an external amp to give it more grunt.

 

[Circle O Willis]

Quote:

Originally Posted by caramelsoul Wikipedia is your friend....

good call, i completely forgot about that...

also i found for relatively simply, but good explanations for a lot of stuff, www.howstuffworks.com is pretty cool. and if they don't have it they usually have a link to somewhere that can help.

thanks carl...i think that's how i've thought about it, maybe just wasn't nearly as good at getting it across.