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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
atdavid
736 posts
 
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.
georgehifi's avatar
georgehifi
10,312 posts
 
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
koestner
621 posts
 
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
736 posts
 
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

mijostyn's avatar
mijostyn
8,160 posts
 
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. 
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