High end Class D amps?


Just an observation and a question. Are there 'high end' Class D amps out there that are just as good as Class A, A/B amps? I realize that's a sensitive question to some and I mean no disrespect---but whenever I see others' hifi systems on social media, all of the amps are A or A/B. There's always Pass, McIntosh, Moon, Luxman, Accuphase, etc. Where are the Class Ds? For folks out there that want more power for less efficient speakers and can't afford the uber expensive Class As, A/Bs, what is there to choose from that's close to those brands? Thanks
bluorion
That value that you quote, EPDR has absolutely nothing to do with max current requirement. It is a synthetic value to represent thermal loading in a linear amplifier. It has no application to Class D amplification.

I suggest going back and understanding this better as your understanding is flawed.
It has no application to Class D amplification.
Of course it does show if it’s capable of driving it.


I suggest going back and understanding this better as your understanding is flawed.
No, I suggest you go and find out what happens to Class-D when it tries to drive low impedances that I’m talking about, see if it can do the wattage doubling act down to 1ohm or even 2ohms as the impedance halves They are lucky to even gain any wattage below 4ohm, they usually start to go backwards especially at 2ohms which is current starving or limiting.

And if you deny that, show some independent test figures of class-D wattage at 8ohm, 4ohm, 2ohm, and 1ohm



I will state again. You clearly do not understand what this term EPDR means. It had absolutely no meaning for a class D amplifier as it does not work in the linear range.  The only figure that matters is lowest impedance which in most speakers occurs where Class D amplifiers have very low output resistance.

Your request for tests from 8 to 1 ohm is meaningless and again has no relation to EPDR and a Class D amplifier.

Whether they current limit or not is representative of maximum power and designed thermal limits. What matters is THD at those power levels.

Until you increase your knowledge of Class D amplifiers and this term EPDR as it applies to amplifiers I feel this conversation will go no where. Unfortunately your knowledge in this area is not sufficient for us to have a meaningful conversation.
I will state again. You clearly do not understand what this term EPDR means.
You have no idea, https://imgbb.com/Zzsqsr0 
If you have, stick one on your test bench and watch what happens with the same input to the wattage figures under 8ohm 4ohm 2ohm and 1ohm loading. Until then please take a pill, and push your Class-D out there beliefs to ones that will believe it.

This argument seems kind of silly. As with class A and class A/B, a class D amp's output power at any given load impedance is limited by its voltage and current capabilities. 

In class A and class A/B amps, the output transistors are dissipating power proportional to the bias current and voltage across them. Most class A amps (although not all) are set up with enough bias to operate in class A only into 8 ohms, switching to class A/B into lower impedance loads. With adequate heat sinking (and a big enough power supply), their thermal capabilities can generally support enough current to double power into 4 ohms and again into 2 ohms (and some even again into 1 ohm), since the voltage across the output transistors carrying the current is lower when they are delivering the maximum current. 

This is where EPDR comes into play, because if the phase angle requires high current while the output voltage is still low, the thermal limits of the amp can be quickly exceeded. 

Class D amps operate differently, since the transistors are almost always either in saturation (where maximum current is flowing, but with very little voltage across them) or turned off (where no current is flowing). The only time they are dissipating significant power is when they are switching from on to off or back (this is obviously a simplification). but this is a small percentage of the time. This is how class D amps can be so efficient. 

But there is nothing about class D amps that would prevent you from building an amp that doubled power as you halved impedance. It's just that there is not the same benefits to do this as their might be in a class A or A/B amp. The amp is not going to run much more efficiently at half the rail voltage like a linear amplifier will. 

Since most speakers are nominally 8 ohms (or slightly less), most class D amplifier designs are optimized for this load.  But that doesn't mean you couldn't build amp to do what you're describing. The Hypex and Purifi modules, for example, can be operated at a lower voltage with the same high-current power supplies to create an amp that can easily achieve what you are talking about.

If you ran a Purifi module at around 35v, it would be limited to about 30w into 8 ohms, 60w into 4 ohms, 120w into 2 ohms, and could probably achieve 240w into 1 ohm. But why would you want to do this since you could achieve almost the same power into 1ohm and get over 200w into 8 ohms without generating much heat by using a higher voltage supply.