Class D amp long term reliability

[dlaloum]

How much do you think a class D amp would cost and how many choices do you think you would have and how reliable would they be in a "command economy"?

There are other economic models... life really isn't black/white!!

I would like to see options available for the typical Class D amp boards (purify, hypex, ICE) that facilitate proper heatsinking, and kit heatsink cases designed to mount those boards....

Yes there is an additional cost to heatsinking and cases - but there is no additional cost to designing the boards so the heatsinking can be facilitated, and if the boards were designed that way, there are plenty of case manufacturers that would provide proper heatsink cases to match.

Then we could move from amps designed for a 5 to 10 year lifespan, to ones designed for a generational lifespan ... 25yrs or more.

I have Quad 303 and 606 amps.... typical lifespan before needing work is definitely measured in decades.... when they do need work, it is typically a couple of capacitor replacements.... under heavy load they only ever get slightly warm - this is the type of design and build that I expect from my amps. - Yes they were then (and Quad still is now) an upmarket option, at a premium, but not over the top excessive, price.

There is an old story about one of the things Rockefeller did when growing Standard Oil (it may be mythical) - most of the oil was shipped in Barrells, so barrel cost was a key substantive cost component - he got some of his workers to make barrells with fewer and fewer welds... and test each iteration for leakage, when he found the leakage point, they added that one additional weld to make it "tight" - and that was the specification for barrells from that time forward.

Longevity.... Safety.... Re-Use - all were not an issue in this value equation - make them cheap, reduce cost to original manufacturer, sell them, and move on.

This comes down to choosing the aspects of "Value" that one Values... pure capitalism only values profit... so unless the buyer (that's us!) impose other values on the sales equation.... we get what we asked for.

 

[EJ3]

Seems like some around here want SOTA performance for $100 with long life. Maybe too much to ask for.

You may not get what you pay for BUT you WILL NOT get what you DO NOT pay for.
Be cheap. Get CHEAP.
Something is going to give.
Either it won't & can't be SOTA (and may live a long life or not).
Or it can be SOTA if you modify it (the be cheap & cost yourself time &/or money method
[& it's longevity is still questionable, what you did or had done may be fine but something else may not be]{which is why it was available CHEAP to begin with})
True quality control has costs. Some are happy to not do it well (or at all).
You pays your money & you takesyour chances.
You may get lucky for a while.
But me, I am not into the aggravation of having some part of my system break, sending it off for repair or replacement
(because there is no dealer in the country that I am in, island that I am on or even the continent that I am on that will work with me).
The majority of my stuff is vintage (by a long shot, now) but I have duplicates (or at least something that can be used in place of) of almost everything.
AND I have found quality techs who will work with me and my sometimes unique desires to be done when something does go wrong. (it will, eventually)
A big thanks goes out to Peter Williams of QuirkAudio for his gracious, continued support of my projects & excellent advice on what not to do (when I have some idea that, while possible, may be unfeasible from a cost/benefit ratio or a technical reason).

 

[antcollinet]

There are two sides to that coin - Class A /B/ AB amps have always been built with decent heatsinks, they generate heat and need the heatsinks to ensure long term reliability.

Because the Class D amps generate so much less heat, they are often sold with minimal heatsinking, or just bolted to the case - for the case to act as heatsink....

Without a means of disposing of the excess heat, the fact that they run cooler and more efficient won't eliminate the risk of overheating... and therefore abbreviated lifetime.

All things being equal - ie: using similar levels of heat management / heatsinks, a class D amp should be more reliable and have a longer lifetime due to much lower temperatures.... But manufacturers leverage the reduced heat emission, to remove expensive heatsinks or heatsink cases.... and the end result is..... variable

Plenty of thermal images of class D amps showing that some of their components are getting seriously hot.... with good heatsinking given class D's efficiency, this should not happen.

Such is life in a capitalist society.

All true - which is again another way of saying it is down to implementation.

Select good quality components and put them into a design where they are neither electrically nor thermally overstressed. Manufacture the device with well controlled processes, and you will have a reliable product.

This has nothing to do with the class of the device, and everything to do with the competence of the design and manufacturing organisation.

 

[JSmith]

implantation

Yes, most people like a good plantation... maybe not an implant though, depends.


JSmith

 

[antcollinet]

Yes, most people like a good plantation... maybe not an implant though, depends.


JSmith

Holy hell - am I blind? . Corrected - thanks.

 

[Sokel]

There are other economic models... life really isn't black/white!!

I would like to see options available for the typical Class D amp boards (purify, hypex, ICE) that facilitate proper heatsinking, and kit heatsink cases designed to mount those boards....

Yes there is an additional cost to heatsinking and cases - but there is no additional cost to designing the boards so the heatsinking can be facilitated, and if the boards were designed that way, there are plenty of case manufacturers that would provide proper heatsink cases to match.

Then we could move from amps designed for a 5 to 10 year lifespan, to ones designed for a generational lifespan ... 25yrs or more.

I have Quad 303 and 606 amps.... typical lifespan before needing work is definitely measured in decades.... when they do need work, it is typically a couple of capacitor replacements.... under heavy load they only ever get slightly warm - this is the type of design and build that I expect from my amps. - Yes they were then (and Quad still is now) an upmarket option, at a premium, but not over the top excessive, price.

There is an old story about one of the things Rockefeller did when growing Standard Oil (it may be mythical) - most of the oil was shipped in Barrells, so barrel cost was a key substantive cost component - he got some of his workers to make barrells with fewer and fewer welds... and test each iteration for leakage, when he found the leakage point, they added that one additional weld to make it "tight" - and that was the specification for barrells from that time forward.

Longevity.... Safety.... Re-Use - all were not an issue in this value equation - make them cheap, reduce cost to original manufacturer, sell them, and move on.

This comes down to choosing the aspects of "Value" that one Values... pure capitalism only values profit... so unless the buyer (that's us!) impose other values on the sales equation.... we get what we asked for.

After all all the specs we read for the usual modules are usually heatshinked (some of them even describe which heatshinks and also when they're not) to meet the numbers we see all the time.

 

[EJ3]

All true - which is again another way of saying it is down to implementation.

Select good quality components and put them into a design where they are neither electrically nor thermally overstressed. Manufacture the device with well controlled processes, and you will have a reliable product.

This has nothing to do with the class of the device, and everything to do with the competence of the design and manufacturing organisation.

Yes, but that does not go along with CHEAP SOTA!
Which is what many (if not most) have been trained to do: get the lowest possible price, no matter the real costs, ie. the lack of longevity, throwaway quality, taking up time, money & resources by constantly having to buy more new stuff, making for extra (unneeded, if the gear had been built for longevity) recycle/waste costs, (time/transport/power/landfill, etc.).
So, even though one thinks one is getting a better deal of front on throwaway cheapness, one loses time & effort replacing it. Individuals also lose as a community because of disposal costs, which affect ones own (as well as everyone else's) tax expenditure allotment (whether the taxes are used to deal with the waste caused by the consumerist attitude of churning replacement gear [& built to not be able to be repaired without great effort that costs to much to do] or to do some other good for the community or for everyone to have a lower tax rate because the products where built to last to begin with and are not being recycled/disposed of.
Naturally, this does not apply to the used gear market, as the quality of the gear that can be reused or repaired & reused (another, better [IMHO] form of recycling is to not have it go to the recycling center but be passed on to another user through the used market (whether it needs to be refurbished or not).
This is the true ecologically sound process: reuse/repair/repurpose & send it out to recycle or the trash bin only when it can no longer be used reuse/repair/repurpose part of the cycle.
Just recycling off the bat, by having it made for cheaper up-front costs:
A. only saves money up front to the initial consumer (because it is a recycle/throw away item by design)
B, costs everyone in the long run.
C. much of the recycling done in the current format (at least with consumer electronics and vehicles [with vehicles many of the parts can be reused if they are not simply destroyed by crushing and burying the results of crushing] {and not crushing & having a good used market for body shops is a model in many areas}) is purely virtue signaling. This occurs because of the "build it as cheap as possible" so that the companies have more things that don't last so that they can make more of them to sell. Planned obsolesce, if you will.
Demanded by the mass of consumers who only want to have things as cheap as possible (who then bitch about the lack of quality as they buy another one because they have to dispose of the first one that no longer functions & cannot be economically repaired).

There, I'm done with my rant, I hope that I made some sense.

 

[dlaloum]

After all all the specs we read for the usual modules are usually heatshinked (some of them even describe which heatshinks and also when they're not) to meet the numbers we see all the time.

Hmmm - most of the "usual modules" have a metal back plate, acting as heatsink, which is bolted to the case for further heat transfer..... and that's it.

To me, that is a very minimal heatsink! - and results in thermal images showing temperatures of over 70c (sometimes over 100c) in places.

If you want circuitry with long life, you need to get those temps down to under 50c in a perfect world - which would necessitate real old style heatsinks, carefully mounted to the critical bits, and/or perhaps some heatpipes - but the components all crammed together makes some of this more difficult.

The other concern I have, is classic high quality class AB amps are relatively simple, and relatively easy to maintain/repair - the same cannot be said for Class D modules.... usually cramming heaps of surface mounted components into a tiny amount of space, making them difficult (never say impossible) to repair.... basically they are engineered to be disposed of and replaced rather than repaired. Disposable economy, disposable culture.... Like mackerel in moonlight, it shines and stinks.

 

[Sokel]

Hmmm - most of the "usual modules" have a metal back plate, acting as heatsink, which is bolted to the case for further heat transfer..... and that's it.

To me, that is a very minimal heatsink! - and results in thermal images showing temperatures of over 70c (sometimes over 100c) in places.

If you want circuitry with long life, you need to get those temps down to under 50c in a perfect world - which would necessitate real old style heatsinks, carefully mounted to the critical bits, and/or perhaps some heatpipes - but the components all crammed together makes some of this more difficult.

The other concern I have, is classic high quality class AB amps are relatively simple, and relatively easy to maintain/repair - the same cannot be said for Class D modules.... usually cramming heaps of surface mounted components into a tiny amount of space, making them difficult (never say impossible) to repair.... basically they are engineered to be disposed of and replaced rather than repaired. Disposable economy, disposable culture.... Like mackerel in moonlight, it shines and stinks.

Coincidentally I posted earlier in another thread a screen shot the data sheet of the amp I use to power my lows,at the top of the pic is described the heatshink they use:

TOPPING RA3 Amplifier（PA5 substitute?）

thank you Mr. 192kbps! despite your low bandwidth name your posts are more like MQA FLAC (no, I'm kidding of course!) A question i have is that why would you have XLR out on the DAC but have whatever the hell TRS input on the amp???? what what? unless they give you an XLR to TRS interconnect...

www.audiosciencereview.com

 

[Galliardist]

Hmmm - most of the "usual modules" have a metal back plate, acting as heatsink, which is bolted to the case for further heat transfer..... and that's it.

To me, that is a very minimal heatsink! - and results in thermal images showing temperatures of over 70c (sometimes over 100c) in places.

If you want circuitry with long life, you need to get those temps down to under 50c in a perfect world - which would necessitate real old style heatsinks, carefully mounted to the critical bits, and/or perhaps some heatpipes - but the components all crammed together makes some of this more difficult.

The other concern I have, is classic high quality class AB amps are relatively simple, and relatively easy to maintain/repair - the same cannot be said for Class D modules.... usually cramming heaps of surface mounted components into a tiny amount of space, making them difficult (never say impossible) to repair.... basically they are engineered to be disposed of and replaced rather than repaired. Disposable economy, disposable culture.... Like mackerel in moonlight, it shines and stinks.

How come vacuum tube products are never talked about in this way? Their "modules" require regular replacement, after all.

 

[Roland68]

How come vacuum tube products are never talked about in this way? Their "modules" require regular replacement, after all.

Because electron tubes are a consumable item that needs to be replaced when it's worn out, like a vacuum cleaner bag.
That should be clear to anyone who buys a tube amp. It is not a maintenance free product, unlike a normal Class A, A/B or D amplifier.

This thread is more about durability problems as a result of poor, ignorant, incompetent or inexperienced development and manufacture.
Likewise, of course, the consequence of insufficient, insufficient or incorrectly adapted components for this application.
And last but not least, it is of course also due to the lack of durability and load simulations under tougher conditions.
Then a problem like the PA5 would have been noticed before production.

 

[EJ3]

A. There are other economic models... life really isn't black/white!!

B I would like to see options available for the typical Class D amp boards (purify, hypex, ICE) that facilitate proper heatsinking, and kit heatsink cases designed to mount those boards....

C. is an old story about one of the things Rockefeller did when growing Standard Oil (it may be mythical) - most of the oil was shipped in Barrells, so barrel cost was a key substantive cost component - he got some of his workers to make barrells with fewer and fewer welds... and test each iteration for leakage, when he found the leakage point, they added that one additional weld to make it "tight" - and that was the specification for barrells from that time forward.

Longevity.... Safety.... Re-Use - all were not an issue in this value equation - make them cheap, reduce cost to original manufacturer, sell them, and move on.

This comes down to choosing the aspects of "Value" that one Values... pure capitalism only values profit... so unless the buyer (that's us!) impose other values on the sales equation.... we get what we asked for.

A. Which of those models give many choices so that you can have CHEAP (perhaps not so long lasting) & more expensive (but likely longer lasting) with many different esthetics available (snake oil or not)?
Please enlighten us. (I am not being sarcastic, I have lived in the USA, Austria, & some communist country that I won't mention). I have property in these three. There are also many other places that I have stayed long term but do not own property in (South Korea, Japan, Australia, & Chuk are a few)

B. There are many options for CLASS D amp boards (due to the ability to make a profit from different setups & at different price points [yes, some are snake oil, but that is the way some choose to spend their money] {and yes, some get duped}). But, now, in a semi-free somewhat (and in many cases, overly so [as the government can ultimately choose winners & losers, whether it is what the consumer wants or not, because a lot of what is wrong is due to the governments choosing for us] regulated production world, we ARE allowed to have someone (AMIRM) form an INDEPENDANT (allowed to test what the government says are supposed to be the tests (or not) as well as what he thinks & perhaps what others suggest) without government interference as to what is tested and how it is tested and to distribute that information on a voluntary basis, only asking for donations (and for that to possibly become a profitable endeavor).

C. So, the barrels were done with perhaps no design except that they needed to be very stout. But testing revealed that they did not need to be super stout. So the level of stoutness was constantly reduced through experimentation (scientific method) until it was not stout enough & then made back to the level that it was stout enough. Thus reducing the use of excess materials, reducing peoples exposure to the amount of welding off gasses (probably helpful to their health, at a time when health was not something on the radar for most people), making the barrels lighter (thus reducing the workers physical stress in handling the barrels, creating less chance for injury), and yet, these barrels are plenty stout to be reused many times before they get so weak & rust that they have to be disposed of.

I see no downside to this unencumbered by government capitalistic exercise in efficiency. (yes, to make more profit [which drives innovation] & admittedly, can create bad situations if their are ZERO rules & regulations {but many rules & regulations are out dated & may in fact be dangerous & need to be revued to be altered or removed
So, even though it (admittedly) inadvertently helping workers health, & the environment, it was a bad thing?
I do not think so.

The government rules & regulations protecting workers making beryllium cantilevers in the 1980's (a good thing, at the time) needs review. Obviously, some people are making speaker parts out of them somewhere these days. Perhaps there are new ways to keep workers safe & make beryllium cantilevers again.
The problem with the regulations is that the government seems to not just tell you what the result should be (ex. keep the workers safe from this product or this is the pollution level that is satisfactory. But then they tell you HOW it must be done. So, if you find a way that it can be done & succeed in the goal but it is not the way that they told you to do it, it cannot be used. Thus the government picks winners & loses by stifling innovation

I had a friend who, in the 1980's, took a 1969 car, built it to meet 1996 new car emission's (including the evaporative emission standard that would be going into effect then),
partially by using a redesign (to flow enough air for the much larger application) Nissan's vacuum air pulse for the catalytic convertors (the 1969 car used 2 of these & 2 3" inlet & outlet catalytic convertors). This style of pulse air system allowed the 1969 car to get better fuel economy, have more power & met or exceeded the1996 emissions standard in every metric (except one).
BUT because this car no longer had the 1969 mandated smog pump, it was given a failure at the emission test station due to not meeting the visual (it was missing a mandated part).
The government regulation stifled the setup that could have been sold to old car owners to meet much newer emission standards.
And improve the air quality much quicker than the rate of old cars just aging out.

That is just one of many examples that I have run into in which the government regulation has great intent but stifles people getting to that intent by innovative means that the government did not foresee and had mandated the process that must be used in order to comply.

Both capitalism and government regulation can be a 2 way sword.

As you say, there seems to be a need for a balance. Getting rid of capitalism (a big driver of innovation) or government (a big driver of safety) is not the answer.
But we have yet to come up with a system that smoothly integrates these things, along with allowing people to be free to choose the winners & losers via our purse strings.

Doing things like Amirm is doing for our hobby is very innovative, in which the people (us, who are members here) are able to, through our support of Amirm's work (and suggestions that Amirm may take) can expose the "greedy" or just plain inept side of things so that the people that wish to, can make better choices, is wonderful.

And I am happy that we have the freedom to be involved in this endeavor.

I am sorry, I was set off on another rant.
Maybe because I have experienced many governments.
None are pure capitalists, so there is no way to experience that.
All have some faults, some seemingly worse than others.

There is no government that I have seen that promotes stereo and other forms of the audio creating & listening experience as a platform, so it has to be us to promote this experience, gear and the quality (or lack there of) and how it can be improved.

Let's please get back to doing what we are here for: stereo and other audio gear, their qualities (or lack there of) and implementations.
And stay focused on our common desires, as opposed to the differences in the style governments available where we live & and elsewhere (even in our minds [unless a government is hampering our ability to enjoy our gear, then we may need to actually address that].

 

[levimax]

I am not a switching power supply expert but I have been building my own PC's for the last 35+ years. I use top quality components including over rated high quality name brand power supplies. In every case of PC I have built the power supplies have always failed first. On average I have to replace the power supplies every 3 to 4 years while the rest of the PC lasts 10 years or more. I am wondering if that will be the case with these class D amps as well. I am not sure if switching power supplies are inherently short lived or not, I have read that the capacitors take a beating which make sense. I have also built and used many linear supplies in amps and they have always lasted decades. Time will tell I guess.

 

[antcollinet]

I am not sure if switching power supplies are inherently short lived or not,

Not - we are down to competent implementation again.

 

[Philbo King]

I am not a switching power supply expert but I have been building my own PC's for the last 35+ years. I use top quality components including over rated high quality name brand power supplies. In every case of PC I have built the power supplies have always failed first. On average I have to replace the power supplies every 3 to 4 years while the rest of the PC lasts 10 years or more. I am wondering if that will be the case with these class D amps as well. I am not sure if switching power supplies are inherently short lived or not, I have read that the capacitors take a beating which make sense. I have also built and used many linear supplies in amps and they have always lasted decades. Time will tell I guess.

You'll find that anywhere production costs are starved to bare mimimum.

An urban legend: When Admiral TVs were in production, one of the executives would come to the design lab and remove parts one at a time until it quit working, then put the last one back in and call the design finished.

 

[levimax]

Not - we are down to competent implementation again.

Looking into this I came across this article about high quality computer PSU failures. https://www.tomshardware.com/news/why-power-supplies-fail-psus,36712.html While I am sure it is possible to create a long life switching PSU to me it appears orders of magnitude more difficult than an old fashioned linear supply with only a handful of heavy duty parts and a transformer which is both inherently durable as well as providing a "shield" to protect more sensitive semi-conductors from being directly connected to the mains grid. I am still skeptical that for the quality of switching PSU we will find in audio equipment that these won't be the weak link for longevity.

 

[Roland68]

I am not a switching power supply expert but I have been building my own PC's for the last 35+ years. I use top quality components including over rated high quality name brand power supplies. In every case of PC I have built the power supplies have always failed first. On average I have to replace the power supplies every 3 to 4 years while the rest of the PC lasts 10 years or more. I am wondering if that will be the case with these class D amps as well. I am not sure if switching power supplies are inherently short lived or not, I have read that the capacitors take a beating which make sense. I have also built and used many linear supplies in amps and they have always lasted decades. Time will tell I guess.

For many of our customers in the industrial sector, switched-mode power supplies run in high-energy applications in 24/7 operation 365 days a year, at least 5-10 years without failure. This at ambient temperatures of 40-50° in a closed and unventilated housing (the air contains everything from oil vapor to metal particles).
However, a 500-1000 watt SMPS is larger than an A4 sheet, 10-15cm high and costs a 4-digit amount (the first digit is not a "1").

Most savings are made in switching power supplies in terms of development time, effort in the circuit, the power transformers and the capacitors. However, the capacitors must absorb all savings and negligence. Since these are often undersized and savings have been made in terms of quality, they naturally give up very early on.

Look how much more complex the cheap series from Mean Well like LPP, EPP, LPS or HRP are. And they are considered low-end in the industrial sector.

It is also interesting that as early as 2000 (until at least 2014) Supermicro servers and WS, but also the business devices from HP/Compaq, ran for 5-10 years in continuous operation under high load, (almost) without mainboard and power supply failures. But they were also significantly more expensive.

 

[antcollinet]

Looking into this I came across this article about high quality computer PSU failures. https://www.tomshardware.com/news/why-power-supplies-fail-psus,36712.html While I am sure it is possible to create a long life switching PSU to me it appears orders of magnitude more difficult than an old fashioned linear supply with only a handful of heavy duty parts and a transformer which is both inherently durable as well as providing a "shield" to protect more sensitive semi-conductors from being directly connected to the mains grid. I am still skeptical that for the quality of switching PSU we will find in audio equipment that these won't be the weak link for longevity.

It is simply a choice that is being made. Design down to a price rather than up to a quality level.

 

[Roland68]

Looking into this I came across this article about high quality computer PSU failures. https://www.tomshardware.com/news/why-power-supplies-fail-psus,36712.html While I am sure it is possible to create a long life switching PSU to me it appears orders of magnitude more difficult than an old fashioned linear supply with only a handful of heavy duty parts and a transformer which is both inherently durable as well as providing a "shield" to protect more sensitive semi-conductors from being directly connected to the mains grid. I am still skeptical that for the quality of switching PSU we will find in audio equipment that these won't be the weak link for longevity.

But that's old hat. In early 2000 through about 2008, during the days of Northwood and Prescott, the problem was 10 times worse. At that time, complete series of mainboards and power supplies were defective under warranty, just think of Asrock's losses.
Have you ever tried a PC power supply from Bicker Elektronik? Very different quality and service, but corresponding prices....

When it comes to amplifier power supplies, you're comparing apples to oranges.
The SMPS, which are built into the cheap ($100 - $250) amplifiers with 2 x 70 - 2 x 200 watts, cost around $10-15. Great that these power supplies work.
Take the money that a normal, conventional power supply (transformer, capacitors, etc.) with the required quality, performance and stabilization (required by almost all Class D amplifiers) costs and you won't have to worry about durability.
For the price you get high-quality power supplies in the audio sector and in the industry.

 

[mhardy6647]

You'll find that anywhere production costs are starved to bare mimimum.

An urban legend: When Admiral TVs were in production, one of the executives would come to the design lab and remove parts one at a time until it quit working, then put the last one back in and call the design finished.

The story is (ostensibly) true, but not Admiral. It was Earl "Madman" Muntz's company (Muntz). The process that would become known as "value engineering" was, in the 1950s, known as "Muntzing". My father was a TV repair person and I know/remember way too much about the televsions of (in particular) the 1960s. Muntz TVs had less complex IF sections, e.g. -- less bandwidth than a 'real' TV, but they did work, and they were cheaper.

Muntz also, briefly, made automobiles.

... and also a four-track cartridge tape player for car hifi -- but Bill Lear (of Lear Jet fame) bettered Muntz with his 8-track.

Automotive History: 1949-1954 Muntz Jet - "I Buy Them At Retail And Sell Them At Wholesale" - Curbside Classic

A luxurious high-performance four seater, with a removable hardtop and solid American production-car underpinnings. Sounds like a winning combination. But as Earl “Madman” Muntz soon found it, it was a […]

www.curbsideclassic.com