Just wondering if anyone can check my physics here. I'm trying to calculate the power I'm getting into my HE-400.
Using the relationship P_2 = P_1 * (R_1 / R_2) (That's power and resistance), I have P_1 = 50 W and R_1 = 8 ohms for the Emotiva, and R_2 = 35 ohms for the HE-400, so P_2 = 50 * (8/35) = 11.4 W.
With 300 ohm serial resistors, I have R_2 = 300+35, so P_2 = 50 * (8 / 335) = 1.2 W. About the same as what a Magni would deliver with no resistors in the chain, yes? Interesting. I'm happy that I didn't get a Magni though. The Emotiva is way cooler.
Does it actually work this way? The Emotiva doesn't have 100 W into 4 ohms, so it seems like this linear model isn't quite right?
You are right about the power part without resistors. The linear model isn't quite right, but I guess that is quite logical ( 0,1 ohm 4kW lolz). Don't think too much about that, though. You need to measure the power output at different impedances to be sure about anything. But 11.4 W is a good approximation anyway, though the number might be a little higher as the amp most likely delivers even higher voltage at higher impedances as the load is easier to drive and requires less power yielding less distortion...
Something tells me you aren't right about the serial resistor thing as what you calculate is the overall power that the resistor + headphone is eating. You only want the headphone power consumption, I guess. In series, the amperrage is the same across both the headphone and resistor. That'll be I=sqrt(P/R), which is around 0.06 A. The voltage of the system is then: U = P/I which is around 20 V, a little more perhaps.
Anywayz, the voltage drop between headphone and ground will be: (35/335)*20V which equals around 2 volts. 0.06 A * 2 V equals a puny 120 mW, though the number is bound to be quite higher. Can explain that as well if you want... Has to do with input sensitivity and depends on your source as well. But no one can know these numbers for sure without measuring.
Correct me if I am wrong, I have no education in electrical engineering or anything like that, except what we've learned in physics, though