AMP Specs

One of the things that I always notice when I’m shopping for an amp is the fact that manufacturers almost never stick to a standard of listing the specifications, particularly with the output numbers.

Some manufacturers will list power output for a few relevant impedance levels (16, 32, 50, 300, 600)
But others will just list a couple (16, 32)

Does any one know if there is a way to get more meaningful information from the provided specs?
In essence, from the known listed specs, is there a way to extrapolate/interpolate the power output for intermediate values? Say, 150 ohms?

And if there are any electrical engineers out there, forgive me. It’s been a while since I’ve taken E&M

1 Like

Ideally, output power would be displayed as a graph with Resistance on the X and Power on the Y Axis at a given frequency (1000Hz for example).

As is, you could break out Ohm’s law (as I did further below) to find out: Without knowing the voltage the amp puts out, your work is very much worthless.
You could offcourse assume the transistors or MOSFET’s * are right at the edge of their saturation region (for semi-conductor based amps, 0.4 to 0.8V), the resulting error bars in the graph make the exercise worthless though.

*(I have no idea how Tubes work)

"This is easy!" he thought

Technically Ohm’s law for AC circuits is to be used. As headphones are only a resistive load, you can still use the DC forumla: U(V) = I(A) * R(Ω)
Insert the above forumla for U in P(W) = U(V) * I(A) to get P(W) = I² * R(Ω) and… this does not help much, does it?

Simple reason: When you change the resistance, the voltage drop changes meaning the current is different.

You can’t.


That makes sense.
So it sounds like it really needs to be tested rather than calculated.

Is there a resource out there that provides results to such testing?

I’ll have to save this for later xD

1 Like