tincanear
Headphoneus Supremus
The Class A vs Class AB refers to the amount of heat generation, with Class A generating a lot more idle heat than a Class AB amplifier of the same output power rating. In the case of the Asgard 2 and Asgard 3 amplifiers, the case acts as a heatsink, so there is a limit to the output power rating (higher rated power = hotter running amp).
For typical dynamic headphones, the efficiency is around 100dB/mW, so output power is ~10mW for 110dB (4 times a loud as a smoke detector). For medium efficiency planars at ~92dB/mW, the output power is ~63mW for 110dB. For most headphones, both Asgard 2 and Asgard 3 will be nowhere near the max power rating.
IOW, the amplifier max power rating (typically measured at 1% distortion???) is not the critical factor (but is often a selling point) unless its under a 100mW for the target load impedance (or rated at 10%THD or higher).
An exception would be the Susvara, which is ~82db/mW IIRC, so peaks of 110dB would need ~630mW, and the A3 should outperform the A2 power-wise in this situation.
To my ears and using a medium efficiency low-impedance (~16 ohm) planar, the A2 (est ~500mW maybe lower, max into 16 ohms) always sounded a bit veiled in the midrange / lower treble, with a somewhat flat soundstage depth. I much prefer the A3's midrange, lower treble and soundstage depth, even though sometimes the bass seems a bit too warm. For my listening, I prefer the high gain mode, and have the volume in the lower 1/4 of its range (nowhere near max rated power).
From an electronics design perspective, the A3's advantage is the Continuity circuit, plus paired-matched transistors. Continuity allows a lower bias current (= cooler at idle) and helps reduce distortion at higher power levels. The paired-matched transistors which help reduce distortion further, are relatively new components and were not available when the Asgard 2 was designed many years ago.
For typical dynamic headphones, the efficiency is around 100dB/mW, so output power is ~10mW for 110dB (4 times a loud as a smoke detector). For medium efficiency planars at ~92dB/mW, the output power is ~63mW for 110dB. For most headphones, both Asgard 2 and Asgard 3 will be nowhere near the max power rating.
IOW, the amplifier max power rating (typically measured at 1% distortion???) is not the critical factor (but is often a selling point) unless its under a 100mW for the target load impedance (or rated at 10%THD or higher).
An exception would be the Susvara, which is ~82db/mW IIRC, so peaks of 110dB would need ~630mW, and the A3 should outperform the A2 power-wise in this situation.
To my ears and using a medium efficiency low-impedance (~16 ohm) planar, the A2 (est ~500mW maybe lower, max into 16 ohms) always sounded a bit veiled in the midrange / lower treble, with a somewhat flat soundstage depth. I much prefer the A3's midrange, lower treble and soundstage depth, even though sometimes the bass seems a bit too warm. For my listening, I prefer the high gain mode, and have the volume in the lower 1/4 of its range (nowhere near max rated power).
From an electronics design perspective, the A3's advantage is the Continuity circuit, plus paired-matched transistors. Continuity allows a lower bias current (= cooler at idle) and helps reduce distortion at higher power levels. The paired-matched transistors which help reduce distortion further, are relatively new components and were not available when the Asgard 2 was designed many years ago.
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, adding a lot of features to the Asgard3 not only makes it more expensive, but makes it into something else that it was not really meant to be. And also, if one wants the features of the 789, why not get it instead?
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