Aah, thank you, JM - that makes a lotta sense.
(The amplifier delivering the greater sound stage depth was a well-regarded Class A tube amp - with, obviously, a much higher level of H2 than a Purify Class D amp.)
Andy
It really depends on what “class D” you’ve been listening too. Not all class D is created equal - some of it is far worse than others.
My experience is that you *can* eliminate the TYPE of distortion that people who hate class AB object to with well designed class D. You CANNOT do this (safely) at very high power levels, as it requires switching frequencies approaching a megahertz and dead times of 10 nanoseconds. And a lot of filtering. This requires “electrically small” components - wavelength-wise, and kilowatt amplifiers tend to violate this. This kind of limits it to power levels that are appropriate for class A (but eliminates the heat, of course). If you’ve been listening to Behringer iNukes, some cheap Chinese kit, or something in a price-point receiver - they are not near as good as class D is intrinsically “capable” of.
Ok, there is some confusion here. You can have RCA inputs only and a balanced design, or a push pull, and so on. I was also a puzzled when you said "no SE, because I have +V and -V". Mmmm.
What is the design you build? (link please
)Aah, thank you, JM - that makes a lotta sense.
(The amplifier delivering the greater sound stage depth was a well-regarded Class A tube amp - with, obviously, a much higher level of H2 than a Purify Class D amp.)
Andy
I definitely need to return to coding my filter to add various type of distortion in the digital domain...
Then have not listened to the right Class D amplifiers. And/or you mistake euphonic distortion for a "better" prerequisite for critical listening.
Ok, there is some confusion here. You can have RCA inputs only and a balanced design, or a push pull, and so on. I was also a puzzled when you said "no SE, because I have +V and -V". Mmmm.
What is the design you build? (link please
Yes, it is not your average Class A.
It sounds absolutely wonderful, though! I built 2 of the 4R version, as they needed to power the 3ohm mids and 2 ohm ribbons of my active Maggies.Here's the link: Alpha Nirvana 39w 8ohm Class A Amp - diyAudio
Andy
No. Push pull amplifier of Class AB and class A, the different is only bias current of output transistors. The measurement different is only harmonic profile of the distortion. If you compare class AB and class A with different topology (not only bias current change), of course they will measure different.
Sound stage is about matching phase and gain in two channel, and no (or small) phase distortion in each channel.
Yes, it is not your average Class A.
Here's the link: Alpha Nirvana 39w 8ohm Class A Amp - diyAudio
AAAAAAH! Ok, that one. Well, that's an intentionally voiced amplifier. Never heard of it but many people like it a lot. It must be good, I would say.
It is single ended because it generated only one hot signal wrt ground.
It can be called a push pull because it uses two Mosfets (one PNP, one NPN) to simultaneously drive the signal from "both sides" and
It is in Class A because the two mosfets are always conducting.
At the same time, it is a bit weird because if I understood correctly the two mosfets do not work in a completely symmetric way in order to not completely cancel even order harmonics. And it still has a subjectively pleasant sequence of decreasing harmonics.
Never heard it, but I am quite sure one can prefer it and it can also get a perception of deeper soundstage and higher dynamics (the latter because of the distortion as well).
Nothing that could not be emulated with some digital processing and more neutral components, of course, whereas to "fix"it in order to make the result more neutral would be more difficult. However, at the end we choose what we like and often we choose what to choose to like, which is absolutely fine.
The reality is you can build a pretty simple class A amp and it will sound pretty good. To achieve the same perceived quality of sound in AB is a considerably more complex design. Then you have to add we come with one of the most sophisticated DSP processors (our brain), when your brain knows what it should sound like it will attempt to adjust. I can remember ( this will date me) getting in my old truck with a factory AM radio and turn it on and it will sound horrible for half a second then the brain kicks in. I think one of the most difficult part for designers and reviewers is to turn off their internal DSP.
Bill
Bill
