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When did class D start to not suck?

sngreen

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Blame the record, not the reproduction gear. Digital has no sound, we cannot listen to digital data, we listen to mechanical waves.
That is what I observed with Musical Fidelity M8 500s amp. It does not seem to be forgiving. But when the material is good, it is beautiful. NAD is just not open enough for my taste, but I did already say it, did not I?
 

sngreen

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What does open mean?
It means that you can close your eyes and walk between the instruments, the stage is wide and deep, the sound is engaging. This is the first thing you hear with NAD, flat stage with the very sterile tone to it, as if every note is coming from the same visual plane. It's the most unrealistic presentation one can think of. Maybe it is their signature, I would not bother discussing it. I have another NAD power amp in my exercise room, fine where it is, just not for the main room. Their 3020 was interesting, but that was back then .. colored or not I preferred Marantz in the 70's.
 

Phorize

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That is what I observed with Musical Fidelity M8 500s amp. It does not seem to be forgiving. But when the material is good, it is beautiful. NAD is just not open enough for my taste, but I did already say it, did not I?
Not here to change your mind, but there are a multitude of good explanations as to why you genuinely experience perceived difference between one adequately measuring amplifier and another, there actually being a difference ranks amongst the worst explanations. It’s not really even an audio related question, it’s more a question as to what the thresholds are to knowing something at all.
 

Vacceo

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It means that you can close your eyes and walk between the instruments, the stage is wide and deep, the sound is engaging. This is the first thing you hear with NAD, flat stage with the very sterile tone to it, as if every note is coming from the same visual plane. It's the most unrealistic presentation one can think of. Maybe it is their signature, I would not bother discussing it. I have another NAD power amp in my exercise room, fine where it is, just not for the main room. Their 3020 was interesting, but that was back then .. colored or not I preferred Marantz in the 70's.
That sounds a lot like speaker characteristics: frequency response and radiation pattern.
 

Koeitje

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I've been buying SMPS PWM power supplies for my desktop PC for a long time and no issues at all after the first cheap one burst a few caps and went thermally intermittent. I also repaired thousands of high end SMPS car amps and most if not near all of the faults where customer use and abuse conditions. So his being snarky with SMPS stuff is not warranted. The NAD does measure well.
And PC hardware is much more sensitive to bad power than audio.
 

Bleib

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I had a t-amp based on ta2020 years and years ago, which is not powerful but it was perfect for the desktop. Used so little power that I ended up using it more than the linear amp I used to have.
 

valerianf

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Did somebody experienced modern class D amps failing after a few years (i.e. 3 to 5 years)?
My older class D amp may be the OEM amp of my car (>5 years).
My guess is that it may be a class D (Sony sound system).
Still working for now.
 

antcollinet

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There is nothing in the architecture of class D that makes it more likely to fail. If anything, due to the higher efficiencies and therefore potentially lower temperatures involved it should (if designed well) be more robust.
 

valerianf

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"There is nothing in the architecture of class D that makes it more likely to fail"
Sorry I completely disagree.
Most of the modern class D modules are manufactured in China.
In their BOM they use cheap local brand of electrolytic capacitors that will be the first components to fail.
It is why I am asking about the last 5 years reliability.
 

voodooless

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"There is nothing in the architecture of class D that makes it more likely to fail"
Sorry I completely disagree.
Most of the modern class D modules are manufactured in China.
In their BOM they use cheap local brand of electrolytic capacitors that will be the first components to fail.
It is why I am asking about the last 5 years reliability.
What does that have to do with architecture? Do you think other class amps do not use similarly cheap components? Is the use of these components inherent to the architecture?
 

antcollinet

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"There is nothing in the architecture of class D that makes it more likely to fail"
Sorry I completely disagree.
Most of the modern class D modules are manufactured in China.
In their BOM they use cheap local brand of electrolytic capacitors that will be the first components to fail.
It is why I am asking about the last 5 years reliability.
That is not architecture, that is design/manufacture.

You note in my post I said "if designed well". If poor quality parts are selected for the design, that is not designed well. And this comment applies regardless of the architecture - it would apply equally to any other class of amp.

By the way - much of everything is manufactured in china. China manufacture (like manufacturing anywhere) can cover the range of quality from poor to excellent. What matters is design quality standards and manufacturing quality standards applied by the specific organisation.
 

ZolaIII

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There is nothing in the architecture of class D that makes it more likely to fail. If anything, due to the higher efficiencies and therefore potentially lower temperatures involved it should (if designed well) be more robust.
IC architecture of class D along with small and crowded PCB (with close and not cooled capacitors on it) as it's usually done that made it cheaper is less able to cope with extreme operating conditions.
Usually paird with lo impedance speakers and used on high utilisation levels is a real reason for the perception of lo durability, truth is using any amplifier like that disregarding of it's typology will significantly lower its life expectations.
 

boXem

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IC architecture of class D along with small and crowded PCB (with close and not cooled capacitors on it) as it's usually done that made it cheaper is less able to cope with extreme operating conditions.
Usually paird with lo impedance speakers and used on high utilisation levels is a real reason for the perception of lo durability, truth is using any amplifier like that disregarding of it's typology will significantly lower its life expectations.
As a starter, most class D amps not belonging to the "toy" category are not IC based.
 

antcollinet

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IC architecture of class D along with small and crowded PCB (with close and not cooled capacitors on it) as it's usually done that made it cheaper is less able to cope with extreme operating conditions.
Usually paird with lo impedance speakers and used on high utilisation levels is a real reason for the perception of lo durability, truth is using any amplifier like that disregarding of it's typology will significantly lower its life expectations.
Again - these are design implementation issues, not architecture issues of the amp class. Think of architecture as "How the amp class works, and how that determines what circuits you need to implement it". Rather than "how those circuits are imlemented in components and mechanical design". There is nothing about how you are required to implement a class D design that constrains the designer to create a less robust design than any other class - on the contrary, as I pointed out, lower losses mean less heat and (potentially - design implementation dependant) better robustness.

For example you can get integrated "chip" class AB amps** - and class AB amps can equally be designed with "close and not cooled capacitors"

**and integreted chip amps are not a reliability issue in any case - if anything it is easier to cool these as a single device than it is for (eg) multiple TO220 packaged transistors, as often used in a typical class AB design.


What can be seen in the market is some manufacturers using the higher efficiency to allow them to make smaller amps, with insufficient attention paid to cooling. However this is still a design choice and implementation issue rather than an amp class architectural issue. For an example of a well pedigreed non far eastern manufactured Cass AB amp also designed too small and with insufficient cooling, look at the Rega IO review here.
 

Andysu

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class d mentioned in star trek
 

Waxx

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I also don't think the architecture is the issue, but what is an issue is the bad build quality of many, and the biggest issue is that IC's go fast out of production so repairing class D amps is a lot harder than repairing Class A or AB amps as parts are harder to find. And repairing an SMD board is also harder than through-hole components. But those are not limited to class D, those are general issues in modern electronics. It's less durable due to the way the systems are build physically, not due to the architecture of the amp.

And yes, i'm also aware of the advantages of IC's and SMD, they are cheaper to build, smaller, and take less natural resources. But they are not a free lunch...
 

Sokel

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I've got an ICEPower based class D amp that is over 12 years old in daily use. For most of that time it was driving some Soundlab ESLs so not like it had an easy life.
I will be more than happy if my amps lasts as long (and their task is a lot easier).
 

olegtern

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9 years of everyday use of icepowers in my subwoofers, still working, and I hope they keep working for some time.

But there was also a less pleasant experience. Some years ago NAD D7050 was dead after 2 years, immediately after the end of the warranty period. The official service offered a repair with a complete replacement of the amplifier board for 60 or 70% of the cost of a new one at that time. I didn’t find a repairman outside the service, and I’m not sure that the repair was possible at all, amp went into the trash bin.

In general, it seems to me that the reliability of class D amplifiers is no worse than that of any other amplifiers. But repairing amplifiers with complex electronics (e.g. DSP) can be difficult or impossible without plate replacement. Before buying an expensive amplifier, good to know how the company service works, including after the warranty period.
 
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