Class A-AB amps vs pure Class AB amps
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Lavane
Lunatic Member
I wouldn't think there is a whole lot of difference. But the few "twin drive", "Spontaneous Twin Drive", "New Class A" etc. amps I've heard did sound good.
I would think having the amp being able to run in Class A at higher volumes is a plus though. I have a Sony ES series twin drive that's going back to its owner that I really liked. Its built well with quality parts. It has a separate Class A chip amp and a class B discrete amp section.
I would think having the amp being able to run in Class A at higher volumes is a plus though. I have a Sony ES series twin drive that's going back to its owner that I really liked. Its built well with quality parts. It has a separate Class A chip amp and a class B discrete amp section.
this is the argument of: "the most beautiful woman" or "the strongest man"
When it comes to "best amp" there are no such thing as absolutes. It is all in the design and implementation, system components, listener preference, etc.
The best amp is the one that sounds good to you
When it comes to "best amp" there are no such thing as absolutes. It is all in the design and implementation, system components, listener preference, etc.
The best amp is the one that sounds good to you
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The article is dated 2008. Look into the First Watt series documentation which is about 10 years later
My favorite is First Watt SIT-3
Single ended common drain Vfet amp, no negative feedback. Arguably the ideal amp design from a "no compromise of sound" perspective. Class A means it is very inefficient as far as current consumption, but that is just fine with me.
A-AB is still an AB amp. It may have a larger window of class A operation, but its still an AB amp. Some AB amps are biased such that you're out of class A at very low power levels. I think the idea is that since most of the time you aren't using all that much power, in theory its better since you're in class A mode most of the time. Whether it is, who knows. Lots of marketing wank about all this.
The Pass stuff is just straight class A, not quite apples to apples here.
The Pass stuff is just straight class A, not quite apples to apples here.
totem
Addicted Member
As mentioned it's all in the implementation whether A, A,B, Hypex or other topologies.
Yes they each have a "sound" but will differ by their individual voicing between models and even the
same brand.
The better your system resolution the more easily class and voicing becomes evident.
BTW the latest non A or A,B traditional designs are now superlative but at the upper
end of the market.
Example the Jeff Rowland 118 in class D at a list of $58,000, these have been out
for a few years now.
Yes they each have a "sound" but will differ by their individual voicing between models and even the
same brand.
The better your system resolution the more easily class and voicing becomes evident.
BTW the latest non A or A,B traditional designs are now superlative but at the upper
end of the market.
Example the Jeff Rowland 118 in class D at a list of $58,000, these have been out
for a few years now.
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The OP seems to be a little confused about what an A/B amp is, I provided the link for him to read and hopefully gain a better understanding. Date of information therefore has no relevance.
qguy
Super Member
Thanks for all the replies.
from the PassLabs Article posted by opnly bafld, it says
"Higher bias doesn’t just move the Class A transition to higher ground – it has a profound influence on the amplifier at all power levels. It lowers the distortion at low levels as well as high levels, as seen in the distortion vs power curves for an amplifier with the bias set at different levels."
so basically a higher biased amp (A-AB amps) will have less distortion vs an AB amp, even if both amps are operating at the same class AB level. The questions is can we hear the difference
from the PassLabs Article posted by opnly bafld, it says
"Higher bias doesn’t just move the Class A transition to higher ground – it has a profound influence on the amplifier at all power levels. It lowers the distortion at low levels as well as high levels, as seen in the distortion vs power curves for an amplifier with the bias set at different levels."
so basically a higher biased amp (A-AB amps) will have less distortion vs an AB amp, even if both amps are operating at the same class AB level. The questions is can we hear the difference
I was thinking more the Pass F5 / Firstwatt stuff, all class A. Beyond a certain power level the amount of heat you get out of a pure class A design just gets to be too difficult to deal with.
My Emotiva XPA-1L monoblocks are rated 35W/250W in Class A/AB. The difference is more noticeable with high quality 3 and 4 piece acoustic jazz recordings. I’d call it smoother like tubes, but not necessarily warmer. I also notice it more with my B&O M70’s than my DQ-10’s. The other big difference is the corner of the room where the amps are gets a lot toastier.
Agreed and thanks for sharing.
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