HI.
by pure chance I came across a forum where there was talk of an onkio whose model if I'm not mistaken is A9555.
someone wrote that it is a digital amplifier. what does it mean?.
what is the difference compared to other analogues? what class does it belong to?
by pure chance I came across a forum where there was talk of an onkio whose model if I'm not mistaken is A9555.
someone wrote that it is a digital amplifier. what does it mean?.
what is the difference compared to other analogues? what class does it belong to?
The digital version is class D, which isn't actually digital in the meaning of the act of course, never stops marketing departments putting nonsense on the front cover.
I think there is an earlier analog version, presumably class B.
I think there is an earlier analog version, presumably class B.
class D is not digital, in its operation it resembles a computer power supply.
why then do they call them that?
why then do they call them that?
"ONKYO A-9555 INTEGRATED AMPLIFIERS
DESCRIPTIONNew VL digital amplifier technology.
Two-channel equipment coupled with a unique implementation of hybrid class 'D' amplification. "
Bruno and others have pointed out that a class-D is actually an analog amplifier, not digital. Perhaps you could call it a switching amp or PWM. Calling class-D "digital" is a common misconception. There do exist "power DAC" amplifiers that could legitimately be called "digital amplifier". "hybrid" implies that the A-9555 is not a typical class-D amplifier, perhaps something like the dynamic switch-mode power supply topology driving a class A-AB amplifier? Class-D amplifiers improve the efficiency and likely power capability, but generally not the sound quality. Many "Audiophiles" are unhappy with the sound of a class-D amp, but recent class-D amps are very good. Most modern electronics such as smart phones and many car stereos are now class-D.
Hi, please note that the amplifier you read about is almost 20 years ago and since then things (at least from the point of view of relative semantics) have changed a bit.
In addition to what others have already well-said, I like to post the link to a (very) nice interview from not many years ago with Bruno Putzeys who is considered somewhat of a head of Class D amplifiers and who answers all your right doubts and requests. 😉
https://www.soundandvision.com/content/bruno-putzeys-head-class-d
Class D is analogue and it takes a lot of analogue, power electronics and PCB design skills to get things right.
Class D was never meant to mean 'digital' and if I understand correctly, the most digital amplifier is Class Z.
Class D was never meant to mean 'digital' and if I understand correctly, the most digital amplifier is Class Z.
Yes and no.
We all know that the marketing of any company and any type of product exploits each and every thing in order to presumably increase sales, but there is always a minimum of truth and then that "minimum of truth" is systematically manipulated by marketing offices. 🙄
However, the term "digital" originates from the SMPS type of power supply and has then become a misnomer for the entire amplifier.
"There is no clear consensus of what the term digital power means in the SMPS community. This can be attributed to a number of factors including the early introduction of digital technologies back in the '70s with the first PWM controller IC, the various levels of digitalization happening in the last decades, and, of course, the creative nature of the marketing brain. In fact, the switching action itself — which gives the whole technology its distinctive denomination — is in essence a digital phenomenon. Despite this confusion, the technological evolution of the modules is historically clear as we will see in this section."
https://eepower.com/technical-articles/digital-power-for-switched-mode-power-supplies/#
We all know that the marketing of any company and any type of product exploits each and every thing in order to presumably increase sales, but there is always a minimum of truth and then that "minimum of truth" is systematically manipulated by marketing offices. 🙄
However, the term "digital" originates from the SMPS type of power supply and has then become a misnomer for the entire amplifier.
"There is no clear consensus of what the term digital power means in the SMPS community. This can be attributed to a number of factors including the early introduction of digital technologies back in the '70s with the first PWM controller IC, the various levels of digitalization happening in the last decades, and, of course, the creative nature of the marketing brain. In fact, the switching action itself — which gives the whole technology its distinctive denomination — is in essence a digital phenomenon. Despite this confusion, the technological evolution of the modules is historically clear as we will see in this section."
https://eepower.com/technical-articles/digital-power-for-switched-mode-power-supplies/#
Yes.
From the same link I posted above:
https://eepower.com/technical-articles/digital-power-for-switched-mode-power-supplies/#
Ulogon Class D is only called D because that was the next available letter in the alphabet.
It was invented nearly 100 years ago, but got its topology name much later.
It started to be mature for musical playback in the 80ies when CD and DIGITAL was the future of audio with all its advantages. Therefore the early adopteres of Class D were eager to associate their products with this great DIGITAL future.
Cheers!
It was invented nearly 100 years ago, but got its topology name much later.
It started to be mature for musical playback in the 80ies when CD and DIGITAL was the future of audio with all its advantages. Therefore the early adopteres of Class D were eager to associate their products with this great DIGITAL future.
Cheers!
I also know this.
I never said otherwise nor did I ever think that D stood for "digital".
And most of all it's all there in the two links I posted some posts above. 😉
Edit to add: Hi Guerilla, do you still have your Snell? 🙂
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I'd rather call it PWM instead of class D. The LM3524/3525 control IC has been around for a long time, used in car amplifiers to control the switching power supply and convert 12V into higher voltage symmetrical rails for traditional class AB/B output stages.
Some of you may remember the Sanyo PA6100 "brick" amp from back in the early 80s, which was the first car amplifier with a switch mode supply that put out close to 100W/ch into 4 ohms if you had 14.4V going into it. It had STK class AB output stages. I repaired a TON of them.
Class D is essentially a PWM topology with a varying duty cycle square wave filtered through a big LP filter at the output. It has nothing to do with being digital in any way.
Some of you may remember the Sanyo PA6100 "brick" amp from back in the early 80s, which was the first car amplifier with a switch mode supply that put out close to 100W/ch into 4 ohms if you had 14.4V going into it. It had STK class AB output stages. I repaired a TON of them.
Class D is essentially a PWM topology with a varying duty cycle square wave filtered through a big LP filter at the output. It has nothing to do with being digital in any way.
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My Snell had bass renovated at a highly regarded speaker repair shop. It looks terrible and still buzzes. Long beyond varanty on the repair cause I was slow to refit, but I will take it back to the shop in the other end of the country and see if they want their name asotiated with such a lousy job.
Cheers!
Cheers!