understanding output power

[g5tar]

could someone explain how i can read the specs of an amp and know if they are appropriate match for certain headphones. i've always gone by recommendation, however i own a c2sa and there doesn't seem to be to much info out- i'm having great luck powering the hd650s but im not sure if you will match well for lower impedance cans -  the output specs are:
 
[size=x-small]25 ohm: 6000MW
50ohm: 6000MW
100 ohm: 3000MW
300 ohm: 1000MW[/size]
 
 
 
 
 

 

[Wildstar]

You mean 1000 mW (milliwatt), not MW (megawatt). 1000 MW is nuclear reactor power levels, hehe.
 
I don't see what your problem is, those specs mean a lot of power. 6W into 25 ohm is probably enough for a HE-6, and for frying the voice coil of an earbud, I would think.

 

[g5tar]

I just cut and pasted that from the audio gd website-

Maybe I misphrased my question....how can one match the specs from a headphone to the specs of an amp- in general are low impedance cans more current hungry than than high impedance cans? I've read sennheisers need a lot of voltage and akgs need a lot of current, but what about headphones like denons or audio technicas?

I may have misphrased my question again I'm still confused

 

[Wildstar]

If you have two cans with the same sound pressure output per watt (efficiency), the one with lower impedance will pull more current, and the one with the higher impedance will need a higher voltage swing.
It's all about the efficiency. Sennheisers are typically considered more efficient than AKGs. The japanese cans I don't know, I have the impression they vary widely.

 

[g5tar]

So it's about efficiency, not max input power? does sensitivity correlate to the ohms/watts rating? This almost seems ambiguous, but I know it's not....



PS. It seems like efficiency would relate to gain...but doesn't gain relate to voltage? Man I should have paid more attention in science

 

[lbj]

You're over-thinking this a bit.  Take your HD650, 300ohm nominal impedance.  Hooked up to the amp you described in your OP, the amp can deliver 1000mW (a LOT of power) before clipping.  Take another hypothetical headphone, less efficient say, but also 300ohm.  It will also take the 1000mW but not play as loudly as the HD650 because it cannot convert the power to sound as efficiently.  Btw, 1000mW into the HD650 will probably fry your eardrums.
 
To expand a bit and hopefully not over-complicate things:  In general, amps deliver about double the power as loads halve in impedance.  I.e., staying with the above example, our amp would deliver about 2000mW into a 150ohm can.  So a lower impedance can is easier to drive louder, because power output of the amp is increased at the lower impedance (as long as the amp is capable of pushing the current, which your cited amp can't do as impedances approach 25ohm).