Is Class D Analog or Digital ?


Wow!!!..what a conversation! I called Music Matters yesterday in San Francisco inquiring about an older Spectral 
Preamp since their an authorized dealer for many years. The salesman I spoke to was not familiar with the DMC-10. He took my phone number and said I'll have someone get back to. I received a phone call today from the co-founder/owner Jay. I asked about the DMC-10.He trashed the piece saying it is grainy, bright and the newer designs are the opposite.
Nothing could be further from the truth. Us Spectral geeks know exactly how those older models sound. I told him I already had made a decision on amps. He asked, which amps are you getting? I said the Nuprime Evolution Ones since
Demiam Martin from Spectral is co-designer. He said don't buy them... their digital amplifiers and I tell my customer's to stay away from them because of that bright digital sound. Wow! I said they are analog amps and Class D is just a category. He said no, the D stands for digital. This is another prime example why so many Audiophiles are skeptical and will not put their toe in the water to go the class D direction.
audiozen
:) it remains me the situation I asked my friends what is the patefon and in the answer I got everything except the true. It is not the problem when the end user make the mistake. We can correct him and gain +1 to reputation. However when the salesman or presenter make such mistake is a different story for me. Such lack of professionalism is rude, not elegant and insulting... especially when the knowledge lay in public encyclopaedia as wiki. My suggestion for most studied meaning of D is Dreadnought! Why not to classify audio equipment with military ship classes. It sounds good... I have Dreadnought class DAC! My friend has Frigate class Amplifier!!!
binary and dual switching have nothing to do with each other.

"it is binary, not digital, and it is quite confusing"    no such thing as a binary mosfet transistor. binary is only a digital term, for the 1+0 reading from the CD or other formats where 1+0 applies.
Congratulations Audiozen, for failing to state what exactly you have a problem with, and then for further obfuscating the issue which was otherwise well enough discussed.

Also, I disagree with your definitions, so lets just part ways as unamicably as we can.
@erik_squires    

Erik....you are confusing an analog Class D amplifier with a CD player. Binary is a single term/method only of how a laser reads the pits on a compact disc. The space in between the pits are "bumps" results in reading pits,bump,pits,bump, 1,0,1,0,1,0.....switching only applies to switching transistors. Mosfet's are dual switching, moving current in both directions. Diode transistors move current in one direction. Just about all Class A/AB amps use switching transistors. Binary only applies to the digital domain and nowhere else. Nothing confusing about that.
...and triodes have been around how long?

Evolution still requires a certain amount of time.  I may not see (or hear) the 'ultimate D' in my remaining life span, but I'd wager there's 'fire bottle fans' that didn't get to hear yours; *S*

And, of course, to each his/her own...'twas always thus.  
I don't know if I agree that class D designs will be better.  A good design is a good design.  As more of a tube guy and building Direct Heated Triode designs, I find the best of all worlds, tone, speed, detail, soundstage, etc.
@atmasphere , *G*, 'digital' can also refer to toes, toes in the water, all that...never mind.... ;)

D is still in it's infancy in terms of development, HO...  I suspect that most of the negative responses is due to entrenched opinions and tastes, but I view it as a goad to improve the breed..

Given the 'improvement churn' of current digital devices, soon the discussion may be rendered moot.  I may be wrong-headed about this, but I sometimes wonder if a processor linked within a Damp to monitor/analyze/'tweak' a signal would be an interesting aside...*shrug*

They're certainly 'speedy' enough to do so...

I suspect that D will win the hearts, minds, And Ears in the long run.
After all, we who know the differences are literally a dying breed.
Sorry...Time Wins, Ultimately.
The TACT 2170 was a true digital amp. It had a digital input although you could install an ADC card if you liked and it stayed digital until the very out put stage which essentially is a power DAC operating I think it was 9 meg PWM. Lyngdorf may still make this amplifier in another form. The 2170 had a crystalline sound with very controlled bass. Very detailed but not the last word in dynamic punch. The amp was awful at driving electrostatic speakers for some reason. In a fully digital system the amp made a lot of sense. You did not need a DAC at all! You could program the amp with crossover and use one per channel biamping. I did this with Divas very effectively out performing Krell KMA 100's which was not easy. I returned to ESLs for which they were not suitable but a great design none the less. 
I should have been more descriptive. A class-D amplifier with a direct digital input to the control stage, would be more akin to a power-DAC. These are often referred to as "direct-digital" or similar. They do not use a separate analog DAC when the input is digital.
georgehifi6,085 posts10-30-2019 3:31pm
atdavid
A class-D amplifier with digital input would be more akin to a power-DAC.
This is just a Class-D amp with an inbuilt dac that can take digital input, these also usually have analog inputs as well if you don’t want to use it’s dac or have a better one.
Similar to the Technics SE-R1 (except it doesn’t have spdif input they put it on their pre, they use their own L&R link in from their own digital preamp with dac to the SE-R1, and have A to D and D to A in the pre)
https://www.technics.com/content/products/r1/images/se-r1-img-product2-ex.png
https://www.technics.com/content/products/r1/images/su-r1-img-product2-ex.png

Here are a couple of links explaining all the Classes of amplification.
https://circuitdigest.com/tutorial/classes-of-power-amplifier-explained

https://www.electronics-tutorials.ws/amplifier/amplifier-classes.html

Cheers George

For those who still don't know:
Class A is for "Always running at maximum power"Class AB is for "Almost Better than class A"Class B is for "Better than class C"Class C is for "Constantly misunderstood"
Class D is for "Lunatics who can't even hear a tree fall in the forest"
atdavid
A class-D amplifier with digital input would be more akin to a power-DAC.
This is just a Class-D amp with an inbuilt dac that can take digital input, these also usually have analog inputs as well if you don’t want to use it’s dac or have a better one.
Similar to the Technics SE-R1 (except it doesn’t have spdif input they put it on their pre, they use their own L&R link in from their own digital preamp with dac to the SE-R1, and have A to D and D to A in the pre)
https://www.technics.com/content/products/r1/images/se-r1-img-product2-ex.png
https://www.technics.com/content/products/r1/images/su-r1-img-product2-ex.png

Here are a couple of links explaining all the Classes of amplification.
https://circuitdigest.com/tutorial/classes-of-power-amplifier-explained

https://www.electronics-tutorials.ws/amplifier/amplifier-classes.html

Cheers George
An analog input Class-D amplifier would best be considered an "Analog" amplifier, since all processing would be, by typical terminology "Analog".
A class-D amplifier with digital input would be more akin to a power-DAC.
@kijanki and @erik_squires have this exactly right.
Its an unfortunate bit that class D and digital coincidentally use a 'D' in a significant way. 'Digital' can also mean fingers but for some reason we don't seem to have that confusion so often.
Words "switching" and "analog" in the same sentence might be confusing, since switching between two voltage levels suggests "digital" operation, but at this point voltage is not the quantity of interest - "duty cycle" (average value) of the square wave is and it is purely analog with no discrete values (steps).  This "analog" average value of the square wave is converted back to analog output voltage by means of filtering.
And BTW< no, the D in Class D was just random coincidence. Class A, B and C were taken, so Class D became class D because it was next.

Also, I prefer some class D to lots of analog amps. :)

You can't go by the class, gotta listen for yourself.
It is analog and switching.

It is not considered digital because there is no A/D stage.  Control of the switching happens in the analog stage.

The latest Technics amps however call themselves true digital amps as they DO convert.  Some will argue that there is no such thing as digital amplifier, but to me the Technics is far enough down that path.