Class D is just Dandy!


I thought it was time we had a pro- Class D thread. There's plenty of threads about comparisons, or detractors of Class D.

That's fine, you don't have to like Class D amps, and if you don't please go participate on one of those threads.

For those of us who are very happy and excited about having musical, capable amps that we can afford to keep on 24/7 and don't require large spaces to put them in, this thread is for you.

Please share your experiences with class D amps!
erik_squires
Really? Just because it uses a linear rather than a crap SMP power supply, doesn't mean it's not Class-D

From Stereophile:
" Although the SE-R1’s huge twin output meters and beautiful anodized-aluminum finish were visually distracting, the marketing of a Class-D amplifier as a separate high-end component was important. This amplifier delivered some of the best reproduced sound at CES 2017. I persuaded Bill Voss to rip the contents of my copy of Rutter’s Requiem to his media server’s solid-state drive. The broad and deep soundstage, imaging, upper midrange detail, and bass extension were thrilling during the system’s rendition of "Lord, make me an instrument of thy peace" and "Pie Jesu." I appreciated the work done by the Technics staff to prepare their exhibit suite with recessed sound-absorbing panels. I left wanting to hear more."

From Audioholics:
" On the amplifier side, the SU-C700 and SE-R1 are utilizing advanced Class D topologies, featuring a couple new acronyms, JENO and LAPC. JENO (Jitter elimination and noise shaping optimization) provides clock regeneration for low jitter switching in the amplifier stage, sample rate converter, as well as a pulse width modulator that feeds the output stage. LAPC (Load Adaptive Phase Calibration) on the other hand is designed to maintain frequency and phase response regardless of loudspeaker impedance, which is a weakness in some Class D implementations. Finally, the output stage utilizes gallium arsenide FETs (field effect transistors) with a claimed switching speed of 1.5MHz."

From Audio Aficionado:
" .I read a blip in The Absolute Sound that the Technics SE-R1 power amp ($18,000.00) is Class D. It uses a linear power supply rather than a switch mode power supply to produce 100 watts per channel. That’s a lot of money for a 100 w/p/c Class D amp. Along with the Technics SE-R1 Class D amplifier they also introduced the SU-R1 Network Audio Control Player preamp ($9000.00) and new SB-R1 Reference Speaker ($27,000.00). Technics calls this system the R1 Reference System."

Cheers George
So George would like you to believe all Class D amps have issues, but this one future amp finally fixes "The class D problem."  and reviews say so.

Hahahah.

BTW, technically this may actually be a Digital Class D amp, given the A/D conversion and processing.

Best,

E
No I didn’t say that Techinics"finally fixes the Class-D problems.
I said:
" they (Technics) seem to address to a certain extent the problems that they all have still"

Cheers George
That's enough class d nonsense for me,I'm saleing all of mine and going to buy more first watts.

Best,

Kenny.
George is correct in categorizing the Technics SE-R1 as a class D amplifier. It uses a pulse-width modulated switching output stage, and it is therefore a class D amplifier by definition. Various architectural differences that it has with respect to most other class D amplifiers, including the ability to accept digital inputs from a mating Technics preamp and keep the signal in the digital domain until it is converted to the PWM signal that controls the output stage, do not change that fact. Statements such as the following, which appeared in this TAS review, are misleading and incorrect in drawing a distinction between class D and digital amplifiers:
Indeed, this is not a traditional Class A, Class AB, or even Class D amplifier. Rather, it is a rare breed known as a “digital” amplifier....

As with Class D amplifiers, digital amplifiers use a switching output stage; however, they accept digital rather than analog input signals. These “digital” amplifiers take in the pulse-code modulation (PCM) signal from a music server or other source and convert those audio data to a pulse-width modulated signal. This PWM signal then drives the output transistors, just as in a Class D amplifier. The difference between a Class D amplifier and a digital amplifier is that the digital amplifier accepts digital data rather than an analog signal.
What would be correct would be to say that a "digital amplifier" in this context is a form of a class D amplifier. And as such, like any other class D amplifier its design must address the issue of output stage switching speed.  And the sonic consequences, if any, of the low pass filter at the output of the amp for which the required bandwidth is a function of that switching speed.

Regards,
-- Al