CLASS A AMPLIFIERS


What are the sonic benefits of pure class A amps? Are they more "powerful"?
charlot
Even 25 watts of class A will run quite warm. If you want to check if your amp is class A, rig up an ammeter onto the power. While playing music at increasing volumes, when the dial/readout starts to oscillate, that's when it kicks into A/B. For that 25 watts, that would be 0.25 amps and that's loud.
The total output is given as 400 watts into 8 ohms and 1000 watts into 2 ohm, I guess that why the full name is Aragon Palladium 1K. They can't really be running that high in class A they just aren't that big and never run really hot just warm. Look at Avalon's (an agon dealer) listing for the claim. They do have enormous power though, huge headroom, never clip to my ears. I use 936 JM/ Focal Electras with them. They have double 7 or 8 inch woofers and they probably drop their resistance to 4-6 ohm at times. I am suspicious, believe me, but I like them anyway.
I could be very wrong about this, but, I thought Aragon's trick was that they offered their rated class A opperation only so long as they were driven into an 8 Ohm load, below which they reverted into class AB. From what I understand the best ss class A/AB amps half their class A output as their class AB output doubles into progresively halved impdedances.
If its not real heavy and real hot its not running an appreciable amount of class A power. I'm not kidding about the hot. My amp ( gryphon antileon signature ) gets so hot you can not keep a hand on it for more than a few seconds when its really cranking. It runs 150W pure class A into 8 ohms 300w into 4 ohms 600w into 2 ohms and 1200w into 1 ohm and 2400w pure class A into 1\2 ohm ! To do this it requires 200 lbs of amp/heat sinks. Any amp that isn't very heavy can not dissipate the heat produced from this output. This is an inherant drawback of inefficient class A operation. Beware of "class A" amps with A/B output stages. These are not class A amps. Reguarding the sound , it is up to you to decide. I love it. One thing is for sure. It is uniformly stable no matter what load it sees. Good class A amps have ENORMOUS power supplies. I'd be surprised to hear of a class A\B that doubles down to 1\2 ohm. So are they better or more powerful ? It depends. If you have speakers whose impedence dips appreciably then they are probably functionaly more powerful. If you have lots of room, dont mind the heat or the aesthetics of a really big amp with questionable waf then yes I think they also produce better sound. This is just my opinion. - Jim
Another aspect to consider is that Single Ended class A amps do not increase their power output in lower impedence loads e.g Pass XA series amps. Which is why you need to consider the speakers efficency in most cases when using pure classs A amplifiers.

Chuck