It's not wattage directly that seems to have the influence on the performance of high impedance dynamics but rather the voltage component of wattage. That seems to be why they do well on tubes and out of solid state amps that can swing enough voltage.
And I wasn't having a loudness conversation.
I was having a quality of sound conversation, but a few people missed it. Badly.
While you're at it, lookup how much current AND voltage the Asgard 3 and ifi can swing in different modes.
You might not like their sound signature/tonality but talking about current and voltage levels does not apply here since they will drive the HD600 to the point of melting it's thin coils.
When it comes to tube amps, it's the 2nd order harmonic distortion that makes the HD series work well with them, not the current or voltage as I also have a Bottlehead SEX which will drive the HD600 to its melting point as the SEX can power small speakers.
I assure you that your ears or the HD600 are broken and end this conversation. You don't have any idea what you are after and sound like just part of the tired old Sennheiser brigade who still believes that the Sennheisers need some magic dust to work properly.
It's a 20 year old argument and you're not breaking new ground here as I have seen folks spend thousands on amps to power the HD series chasing that dragon of some magical sound that appears from these when you power them with unobtainium amps.
Back to RME discussion now.