You shouldn't base an amps ability to power headphones purely based on their power output. The Lyr is known to not have the ability to power the HE-6 and many have said that it struggles with the HE-4, yet it has a much higher output power than Ember. Power isn't everything. I don't understand it myself, but the Magni has about equal output power as Ember at the low impedance yet it struggles greatly with the HE-4. As many have said, you can't judge equipment you haven't listened to. Maybe someone who knows more about amps can educate us both on this matter, all I know is what I've heard.
First, I think I need to retract my statement about issues with the Lyr + HE-6 pairing. I got confused with the Asgard . I've edited my post.
I think it comes down to the type of power. Let me explain:
We'll start with a simple equation.
P is wattage, I is current (measured in amps), and V is voltage. Let's say that the HE-4 needs 2 watts to sound "good". According to this equation, there's more than one way to get to 2 watts. You can either increase voltage or increase current.
Increasing voltage is generally pretty easy for most electronics, supplying the proper current, however is another story. If the amp isn't actually strong enough to supply the necessary current, then the signal will get distorted and sound lifeless.
The same can happen with the voltage. If the circuitry cannot keep the voltage stable then a drop in current will result.
This is an oversimplification of the issue as there are many other factors as resistance in headphones (and all speakers for that matter) changes with the frequency as well, but hopefully it helps explain why a quality amplifier matters. Maybe someone with more knowledge can chime in as well.
Also, many manufacturers may use the simple V=IR equation to figure power. Where V= Voltsge supplied, I = Current (measured in amps) and R = Resistance of the headphones. This isn't going to result in real world power output, but figurative numbers instead. This is likely why budget amps claiming high numbers don't sound good on phones that need stable current and voltage.
Since the power values are already given (i.e. X watts into Y impedance), and most people are under the assumption that power (AKA watts) is the only unit that matters when driving headphones, it doesn't answer the question of why Ember, with about a third of the power output of Lyr, can still power the HE-6. "HE-6 sounds, quite simply, Amazing driven by Ember". Yet here is a post that says the Lyr is pretty much pathetic with the HE-6. Followed by a post which says what I've been trying to say, power isn't everything.
Edited by Thujone - 11/30/13 at 1:30pm