[Thujone]

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=IV
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.

 

[Modular]

   
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.

 
 
I agree that power values are useless - but only if they aren't an accurate representation of what the amp can produce under a real, dynamic load. For example, if I can sprint at 15 MPH for 5 seconds and then have to stop, doubled over to catch my breath, I can still claim that I can run 15 MPH. I sure as hell can't do it for a full mile though!
 
In the same way, an amp company can claim 1.5 watts at 50ohms, but what if the amp can only provide that for 1/10th of a second. It's going to be clipping in the real world and sound like crap. Or what if the design of the amp causes erratic voltage swings at those high power outputs? It's gonna sound like crap.
 
 There are many reasons that an amp could under-produce it's claimed wattage - probably the most important one at the really high power levels is the power supply. There's a reason that Garage1217 sends out quality PSU's with their units. If the power supply unit needs to "double over to catch it's breath" then the next note in the song you're listening to isn't going to be supplied with the proper current/voltage. 
Here's an example of that from the same thread you quoted: http://www.head-fi.org/t/529873/amps-that-can-drive-the-hifiman-he-6-planar-headphones/1770#post_9819658
 
In the end, there are many reasons that many higher power amps aren't actually performing, but I think it's very quantifiable and isn't merely subjective. 

 

[Thujone]

I agree that power values are useless - but only if they aren't an accurate representation of what the amp can produce under a real, dynamic load. For example, if I can sprint at 15 MPH for 5 seconds and then have to stop, doubled over to catch my breath, I can still claim that I can run 15 MPH. I sure as hell can't do it for a full mile though!

In the same way, an amp company can claim 1.5 watts at 50ohms, but what if the amp can only provide that for 1/10th of a second. It's going to be clipping in the real world and sound like crap. Or what if the design of the amp causes erratic voltage swings at those high power outputs? It's gonna sound like crap.

 There are many reasons that an amp could under-produce it's claimed wattage - probably the most important one at the really high power levels is the power supply. There's a reason that Garage1217 sends out quality PSU's with their units. If the power supply unit needs to "double over to catch it's breath" then the next note in the song you're listening to isn't going to be supplied with the proper current/voltage. 
Here's an example of that from the same thread you quoted: http://www.head-fi.org/t/529873/amps-that-can-drive-the-hifiman-he-6-planar-headphones/1770#post_9819658

In the end, there are many reasons that many higher power amps aren't actually performing, but I think it's very quantifiable and isn't merely subjective. 

Amen, buddy! Peak power levels are often times the only ones mentioned, and that doesn't say much. There are still many pieces in the puzzle, and while I won't pretend to know it all, I know what I hear. I think it's safe to say (IMO, lol) that Ember is more than adequate for the HE-4. Now will someone else just buy one and back me up?!

 

[Happy Camper]

Current reserves are the key.If an amp can't give the instant current for the duration, the soundstage will collapse and the sound will dull out. With proper current delivery, the soundstage stays expanded and the bass attack is vicious. The dynamics are remarkable. The hunt for a good amp for the HE-6 has taught me the amount of wattage isn't as important as the quality of the power supply. A quality supply will have plenty of current reserves and a large enough transformer to provide stable voltage without stalling.

 

[Thujone]

Current reserves are the key.If an amp can't give the instant current for the duration, the soundstage will collapse and the sound will dull out. With proper current delivery, the soundstage stays expanded and the bass attack is vicious. The dynamics are remarkable. The hunt for a good amp for the HE-6 has taught me the amount of wattage isn't as important as the quality of the power supply. A quality supply will have plenty of current reserves and a large enough transformer to provide stable voltage without stalling.

Ahhh. That makes some sense, thanks! So what amp have you settled with?

 

[Happy Camper]

I'm still searching. The amps that have been game ending are in the 8-10k range so I'm just getting the window smudgy staring. I'm using a pair of monoblocks that drove my stat speakers decently. I took them off my rear channels of my home theater speakers. As has been mentioned, it's not so much the amount of power but I've found that the higher wattage amps have the current reserves. That's why we use them. The HE use no where near the wattage but it's the capacity that offers the reserves.

 

[Thujone]

Yikes, head-fi is a true wallet emptier. I am fairly confident that Project Ember is my end-game hybrid amp, but that's because I have already been scared away from diminishing returns. As soon as I make it to a big meet and get to listen to new equipment, I'm sure I'll find myself itching to move up. That or I'll just end up buying and HE-6, haha.

 

[koiloco]

  Yikes, head-fi is a true wallet emptier. I am fairly confident that Project Ember is my end-game hybrid amp, but that's because I have already been scared away from diminishing returns. As soon as I make it to a big meet and get to listen to new equipment, I'm sure I'll find myself itching to move up. That or I'll just end up buying and HE-6, haha.

Just wait till you hear your HPs on something that has more pwr reserve than Ember.  You might be surprised at the improvements!  I used to think my Fiio E9K was quite adequate at driving my HE500, no clipping, no distortion, no problem  then came something else that really opened up my eyes and ears... But if you are happy now with Ember, stay that way.  You will save a lot of $$$.  

 

[Thujone]

  Just wait till you hear your HPs on something that has more pwr reserve than Ember.  You might be surprised at the improvements!  I used to think my Fiio E9K was quite adequate at driving my HE500, no clipping, no distortion, no problem  then came something else that really opened up my eyes and ears... But if you are happy now with Ember, stay that way.  You will save a lot of $$$.  

I think the Emotiva mini is in my crosshairs at the moment... If I don't see any improvement with that, I'll stop for sure! (maybe)

 

[koiloco]

  I think the Emotiva mini is in my crosshairs at the moment... If I don't see any improvement with that, I'll stop for sure! (maybe)

For me, I have stopped after the WA22 and how the Emotiva's compared to the Woo for $200 at driving HE500.

 

[preproman]

^^ WOW that sounds like a win for the speaker amps...

 

[Thujone]

 
For me, I have stopped after the WA22 and how the Emotiva's compared to the Woo for $200 at driving HE500.

So the Emotiva is on par with the WA22? Only an order of magnitude less money too!

 

[koiloco]

  So the Emotiva is on par with the WA22? Only an order of magnitude less money too!

It's quite subjective as you know it already! but personally, I prefer my HE500 on the Emotiva though it's not as detailed and smooth as the WA22.
For other HPs such as my Q701 and the soon incoming HD800/T1, the WA22 does a better job.

 

[Thujone]

 
It's quite subjective as you know it already! but personally, I prefer my HE500 on the Emotiva though it's not as detailed and smooth as the WA22.
For other HPs such as my Q701 and the soon incoming HD800/T1, the WA22 does a better job.

Yeah, that makes sense to me. The higher output impedances on the Ember provide for a more tube-like sound and I do not prefer it on my planar headphones. I prefer the edgy SS sound for the edgy orthos. My HD580's are much more enjoyable on tube amps or when I increase the impedance on Ember. (Laid back)^2, if you will.

 

[hemipowered007]

You get that emotiva yet thujone??!!! I'm awaiting you're opinion.