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Does this mean Class D amps are in fact digital ?

#62
LiptonJigglers said:
You'd be getting closer to the truth if you said the D in Class D stands for Disposable.
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I disagree. EVERY class d amp that I have designed in the last 20 years is still fully serviceable, and fully supported. There are countless folks here who have received such support, contrary to your opinion.
 
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#63
Wild_Bill_57 said:
View attachment 5095213
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#65
agedhorse said:
I disagree. EVERY class d amp that I have designed in the last 20 years is still fully serviceable, and fully supported. There are countless folks here who have received such support, contrary to your opinion.
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That’s because unlike some other popular brands, you’ve built your Mess Class-D amps using extremely high quality components and then you double down with best in class support. Other brands took the opportunity to mass produce on the cheap where repairs are not only months in duration, but cost about as much as replacing with new. Hence the inaccurate generalization.
 
#66
tshapiro said:
Other brands took the opportunity to mass produce on the cheap where repairs are not only months in duration, but cost about as much as replacing with new.
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This is nothing new. The trend in consumer electronics for at least forty years has been to replace entire circuit boards and subassemblies rather than do component level troubleshooting. This has two benefits, the first is no training of technicans is required and the second is that board swapping is faster.

My in-town TV/applicance shop (there's a dying breed) has been doing fixed labor rate repairs for decades. There's only two rates, minor repairs and major repairs and most of the difference is how complicated the disassembly is and how many subassemblies need to be swapped out.

Some devices are so inexpensive that repairs don't make sense. I remember going into a store during the "back to school" season and seeing a display of $2 pocket calculators. As an engineer, I was curious how they could be so cheap. While looking at one when I realized there was no battery compartment cover! For $2 why would you ever bother to change the batteries?

Even large, expensive devices may simply be replaced during warranty. Why have a local shop waste time trying to figure out what's wrong when it's easier to ship out a new unit by 2-day air, include a prepaid shipping label to return the defective unit and let factory techs fix it for resale as a refurb.
 
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#69
Class D has been marketed as digital. It started when digital was used as a selling point. Class D is a different form of an energy conversion process.

It would be nice if heat from amplifiers could be harvested and repurposed. Other than a space heater.
 
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#71
tshapiro said:
That’s because unlike some other popular brands, you’ve built your Mess Class-D amps using extremely high quality components and then you double down with best in class support. Other brands took the opportunity to mass produce on the cheap where repairs are not only months in duration, but cost about as much as replacing with new. Hence the inaccurate generalization.
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I am not alone in this. Genzler, Mesa and Bergantino, are two examples off the top of my head.
 
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#72
brianrost said:
This is nothing new. The trend in consumer electronics for at least forty years has been to replace entire circuit boards and subassemblies rather than do component level troubleshooting. This has two benefits, the first is no training of technicans is required and the second is that board swapping is faster.

My in-town TV/applicance shop (there's a dying breed) has been doing fixed labor rate repairs for decades. There's only two rates, minor repairs and major repairs and most of the difference is how complicated the disassembly is and how many subassemblies need to be swapped out.

Some devices are so inexpensive that repairs don't make sense. I remember going into a store during the "back to school" season and seeing a display of $2 pocket calculators. As an engineer, I was curious how they could be so cheap. While looking at one when I realized there was no battery compartment cover! For $2 why would you ever bother to change the batteries?

Even large, expensive devices may simply be replaced during warranty. Why have a local shop waste time trying to figure out what's wrong when it's easier to ship out a new unit by 2-day air, include a prepaid shipping label to return the defective unit and let factory techs fix it for resale as a refurb.
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In some cases, especially for complicated technology, it is actually less expensive to replace modules or PCBs.
 
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#73
One of the advantages of board-swap repairs is turnaround can be really fast -- swap the board, test, and then deal with the affected board later. If the problem ends up being reasonably repairable the board can be fixed and put back in the parts stack.

Not that I know whether this is how agedhorse and his peers do repairs. I briefly worked at a shop in the 90s that did off-warranty service for Apple products (first question we asked customers is whether their system was still covered, and if so they got referred to the authorized shop in another part of town) and this was a pretty common process in that field.
 
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#74
gln1955 said:
I asked my most trusted source, ChatGPT.

Are class D amplifiers digital?

ChatGPT:
No, Class D amplifiers are not inherently digital. While they are known for their high efficiency and are commonly used in digital audio systems, they are still analog amplifiers at their core.

Class D amplifiers use pulse width modulation (PWM) to convert the analog audio signal into a digital representation. This digital representation is then used to generate a high-frequency signal, typically in the megahertz range, which is amplified and then filtered to reconstruct the original audio waveform.

However, despite the use of digital techniques in the signal processing, the output of a Class D amplifier is still an analog waveform that drives the speakers. The primary advantage of Class D amplifiers is their high efficiency, which allows them to deliver more power to the speakers while generating less heat compared to other amplifier classes.
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Chatgpt seems to want it both ways. It says it’s not digital, then it says digital for a while, but the output to the speaker is analog. Well, that’s also the case with my iPhone. Very suspicious!
 
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#78
I'll say, with regard to Class D longevity... the one distinction my Fender Rumble head had under its belt that I'm certain none of my other heads could achieve is... falling off the roof of a moving car in an incident that just about destroyed the enclosure... and yet the most consequential damage on the inside, to the circuit, was that the cooling fan's blade assembly popped out of its magnetic enclosure. I don't know how they did it, but those heads are ridiculously durable with regards to the construction. I continued gigging regularly with that amp for years after said incident.
 
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