While it probably IS true that a 'cheapo' linear/traditional supply is more reliable than a typical SMPS, it doesn't include the full spectrum of possibilities.
The stuff on Ebay is designed under extreme pressure to reduce cost. If you're OK with that, it won't bother most of us here. But please realize that the product's reliability is likely lower than that of a work-a-day linear.
Cheers
The stuff on Ebay is designed under extreme pressure to reduce cost. If you're OK with that, it won't bother most of us here. But please realize that the product's reliability is likely lower than that of a work-a-day linear.
Cheers
There is another important consideration: Most high power pro amplifiers have a PFC stage in the power supply so they can use AC power much more effectively.
An example of engineering insanity at its finest: https://www.powersoft.com/en/product/duecanali-6404-dsp/#specifications
Lacking punch (dynamics) because of the SMPS? I think not.
The energy in the capacitors are replenished at 100/120 Hz (full wave rect.) or 50KHz or so in case of a SMPS.
Large ripple amplitude at low frequencies or a relatively small ripple amplitude at high frequencies.
Pick your poison.
Anyone working in industrial applications knows that linear PSUs in general outlive SMPS big time. Last year I saw Benning high power linear 48V DC rectifiers that were in continuous use since 1995..1998. These rarely fail. Its SMPS successor used at more recent sites had already been replaced for an again newer version and sometimes even more than once. It is anecdotical of course but many techs know the same and don't trust SMPS as much as linear power supplies of which they speak kindly as they did not have to replace those. Industrial open frame linear PSUs like those by Power One, Condor etc. can be in use for 30 years and still are reliable. Power quality is also better.
In very high power applications as I am used to SMPS is the way to go as losses, weight and size count a lot. Power efficiency as a reason to use SMPS below 50VA in audio really is a non reason as even as SMPS are more efficient, they are powered 24/7 while linear PSUs generally have power switches and are switched off when not used. Using cheaply produced Ebay/Aliexpress stuff and justify that as technically better is nonsense. It is just wasting oil and metals to throw away products that end up either in landfill or again in China to be used for new cheap stuff.
If we desire to be green we maybe should think again what is less detrimental for the environment in ALL aspects over a products complete lifespan and from country of production to EOL.
In very high power applications as I am used to SMPS is the way to go as losses, weight and size count a lot. Power efficiency as a reason to use SMPS below 50VA in audio really is a non reason as even as SMPS are more efficient, they are powered 24/7 while linear PSUs generally have power switches and are switched off when not used. Using cheaply produced Ebay/Aliexpress stuff and justify that as technically better is nonsense. It is just wasting oil and metals to throw away products that end up either in landfill or again in China to be used for new cheap stuff.
If we desire to be green we maybe should think again what is less detrimental for the environment in ALL aspects over a products complete lifespan and from country of production to EOL.
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That might be the most important and overlooked point of the discussion here we usually don't take into account when creating hobby projects
What can be said thought is, that build quality generally getting better, eg. the longevity of PC PSUs increased over the years, that's the warranty table from Seasonic, delivering efficiency of over 95% around 50% load. That's just very impressive and shows that it can be done properly.
I want to second Paul though, there is no point in buying cheap stuff!
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As I worked in China I have seen the pollution and damage to rivers and such. It surprised me that Diesel cars are forbidden for private use and 2 stroke engines were already forbidden as well. Still one has a metal taste in the mouth the first 3 days. Now that air won't stay in China. Even if such large populations live like angels then the impact on the environment still is immense.
The paradox is of course that we all need work to pay our bills and we all want or really need new stuff now and then. The way things are now is far from green as products live shorter by the year. We start to count when the device is delivered to our doorsteps and we stop counting when it leaves our home. Most of us already accept that for example a washing machine needs to be replaced after 4 or 5 years. When I was at school I got the +20 year old washing machine from my granny. It would not surprise me if it still is running somewhere in Africa.
Big supporter of true circular design, that is a way to deal with it. Lithium batteries should have never been accepted for general use while no recycling solution had been thought out. Same counts for phone chargers with each and every brand its own connectors. Wind turbines and solar fields without suitable storage of energy exactly the same. Pseudo solutions wasting oil, energy, water and precious metals. True/real energy saving is simply not using the energy, not "clever" solutions to continue our way of living.
Fabian, computer PSUs should be SMPS with that amount of power. Audio is entirely a different case. We are now accepting technically less good short living PSUs for what reason exactly?! Who seriously thinks a 24/7 powered on SMPS is the way to go to power a 5V 1A (often using 0.25A max.) also 24/7 powered on DAC?
The paradox is of course that we all need work to pay our bills and we all want or really need new stuff now and then. The way things are now is far from green as products live shorter by the year. We start to count when the device is delivered to our doorsteps and we stop counting when it leaves our home. Most of us already accept that for example a washing machine needs to be replaced after 4 or 5 years. When I was at school I got the +20 year old washing machine from my granny. It would not surprise me if it still is running somewhere in Africa.
Big supporter of true circular design, that is a way to deal with it. Lithium batteries should have never been accepted for general use while no recycling solution had been thought out. Same counts for phone chargers with each and every brand its own connectors. Wind turbines and solar fields without suitable storage of energy exactly the same. Pseudo solutions wasting oil, energy, water and precious metals. True/real energy saving is simply not using the energy, not "clever" solutions to continue our way of living.
Fabian, computer PSUs should be SMPS with that amount of power. Audio is entirely a different case. We are now accepting technically less good short living PSUs for what reason exactly?! Who seriously thinks a 24/7 powered on SMPS is the way to go to power a 5V 1A (often using 0.25A max.) also 24/7 powered on DAC?
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An example: I use 12V for the touch power circuit I use for my designs.
Using a small transformer, bridge, and cap for this, it used 3 Watts of power. I replaced it with a small SMPS and this dropped to 0.6 Watts. the linear version uses 5 times the power! This adds up quickly if you have many people running many DACs etc.
Also, RE the small SMPS... I have more than 10 of them in use 24/7 for more than 5 years so far in boxes that can hit 75°C with zero failures. The electrical savings has paid for them by now, too.
For one offs and DIY stuff, sure! build the linear supply with parts from the junk box, but if you're designing something from the ground up and you need to buy all of the parts anyway, sometimes the SMPS is just smarter.
I agree, my comparison was a bit of apples and oranges comparison. But I wanted to point out that there are good and reliable things out there. We often choose cheap instead of reliable, and as you stated correctly waste materials and energy by doing so.
There must be something wrong with that linear PSU. 3 Watts while doing nothing is odd and would be forbidden to be used in the EU. I would like to see how that one is constructed. It won't be an LDO and/or a task specific design I guess which would make the comparison awkward/flawed. As low cost seems to be the driving factor both PSU's likely are selected on low cost.
For me the challenge is to make linear PSUs as efficient as I can while still maintaining ultra low noise and all the positive items. I don't do standby power and that kind of luxury items and switch everything off after having witnessed fire damage because of failed SMPS. Even if the linear PSUs would be plain bad in efficiency they are switched off after a few hours of use per day making the difference in annual power consumption less if not favorable for the linear PSU. They also probably outlive me. Most important is that they give best performance. Nice metal casework and quality appearance help to like them. At first cost is no object, quality is paramount. Then I try to downscale costs while trying to maintain the same quality. I explain it wanting Mercedes Benz quality for a FIAT price. Literally nothing is chosen with low cost as first thought! No generic design is chosen either, all is purpose built to have optimal performance for that device. The connectors used are already more expensive than an SMPS.
Secondly a touch circuit is not audio isn't it? I mentioned a DAC. The sentence was "Who seriously thinks a 24/7 powered on SMPS is the way to go to power a 5V 1A (often using 0.25A max.) also 24/7 powered on DAC?". Would you trade clean power for efficiency and low cost (tempting, I get it) when it is about 1.25W of consumed power? A shorter living SMPS, a DAC that is running a high total hour count while not being used and will EOL sooner than necessary and finally a noisier environment that does not correlate with the wish for best audio performance . All because of cheap. I am glad for you that you succeed in finding peace and happiness in cheap. Wish I could but I am glad I can't.
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That transformer you get hot and draw 3W with no load...
And I obviously know a touch power circuit isn't audio, but you obviously know the comparison is about efficiency and in that case the usage doesn't matter.
And yes, I would simply because the SMPS is 1/4 the size.
The only SMPS I've had fail were being cooked and abused, or just cheap garbage (like a 50$ computer ATX rated for 500W) and almost always I repaired them by replacing the main electrolytic caps (with better ones as to not have to do the job over and over).
And I obviously know a touch power circuit isn't audio, but you obviously know the comparison is about efficiency and in that case the usage doesn't matter.
And yes, I would simply because the SMPS is 1/4 the size.
The only SMPS I've had fail were being cooked and abused, or just cheap garbage (like a 50$ computer ATX rated for 500W) and almost always I repaired them by replacing the main electrolytic caps (with better ones as to not have to do the job over and over).
If efficiency is the main goal then why waste energy by using SMPS in very power inefficient DIY tube amplifiers? Class A amplifiers? In other words the most ungreen mucho Watt consuming devices in audio.
Sounds somewhat contradictory. The usage does matter as audio is our passion isn’t it!?!?
In the example DAC I mentioned (it is playing as we speak) a 5V 1A linear PSU performs a factor of a few hundred to a few thousand times better with regards to noise, consumes no power at power off, wins in terms of annual power consumption, is cheap to build, does not emit EMI, is very reliable, can be reused, makes that DAC live longer, is safer and it is only twice the size of a wall wart. Not too shabby alltogether. One would almost forget that it makes the DAC sound a lot better.
Sounds somewhat contradictory. The usage does matter as audio is our passion isn’t it!?!?
In the example DAC I mentioned (it is playing as we speak) a 5V 1A linear PSU performs a factor of a few hundred to a few thousand times better with regards to noise, consumes no power at power off, wins in terms of annual power consumption, is cheap to build, does not emit EMI, is very reliable, can be reused, makes that DAC live longer, is safer and it is only twice the size of a wall wart. Not too shabby alltogether. One would almost forget that it makes the DAC sound a lot better.
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I see lots of people go to McDonalds and order a double Big Mac, a large fries, and a diet coke... Same difference? 
My tube amps mostly use linear for B+ and SMPS for heaters/bias. There are a couple that use linear for heaters, but I prefer the SMPS seeing as it weighs a fraction, is much smaller physically, and only costs 13$. The linear PSU I made for the heaters cost well over 100$.
My DAC uses an SMPS and it's on 24/7...
Here is a picture of it in a different device. I have the DEQ2496.
My tube amps mostly use linear for B+ and SMPS for heaters/bias. There are a couple that use linear for heaters, but I prefer the SMPS seeing as it weighs a fraction, is much smaller physically, and only costs 13$. The linear PSU I made for the heaters cost well over 100$.
My DAC uses an SMPS and it's on 24/7...
Here is a picture of it in a different device. I have the DEQ2496.
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