If you don't own things for very long, you wont get to see the SMPS failures. Swollen and Bulging Caps seem to be one cause. Burning and overheating boards are another.
I've had multiple SMPS deaths over the decades, mainly for PCs. My most recent was 4 years ago when a SMPS in a Plasma TV began acting wonky on startup. I opened her up and found Bulging Electrolytics - which I replaced - heading off big problems. A year later I replaced it with a 4K TV.
Better examples of reliability are out there: I have a Silverstone PC SMPS that is now 8 years in service. A friend has a Dell PC over a decade in Service. So, the premium Computer SMPS's seem to be competent. They are designed for Gamers who Overclock, install Absurd Video Cards etc. If the customer is willing to pay a premium for a reliable SMPS with better parts and better engineering - it seems it can be done! Gaming PC SMPSs seem to have some really tough requirements to meet. Go look at the 12V and 5V supply currents that an Nvidia graphics card, or an 8 Core Xeon wants. Then again, people are willing to pay $150-$200 and up Just for the Power Supply! If the demand for quality is there, the market can meet it at a good price point.
I had am SMPS die 15 years ago that forewarned me w/ faint Eau de Burning Resistor for about a week. When it went - it took everything including the hard drives with it. This was not a Lightning Strike or Grid Transient - it was an ageing power supply the metastases to the load. I believe this SMPS was in the CompUSA era of cheap Chinese crap sold at discount prices.
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I don't know if the industrial SMPS would be good choice.
We have SMPS in our control panel for decades and run 24/7 with dust, heat and you name it in a manufacturing floor. And those brands with good name rare rarely fail.
The ripple noise is also small, for example some Phoenix PS can have 30mv PP and connect a max 3000 uf capacitor if wished.
The price is little bit high.
We have SMPS in our control panel for decades and run 24/7 with dust, heat and you name it in a manufacturing floor. And those brands with good name rare rarely fail.
The ripple noise is also small, for example some Phoenix PS can have 30mv PP and connect a max 3000 uf capacitor if wished.
The price is little bit high.
I've been working in industrial automation for more than 3 decades... used a fair (a large) number of SMPS. They do fail... electronic parts do fail in general, as do other decoupling caps used in electronic devices in general, as well as in linear power supplies, that are exposed to heat and rail voltages close to their nominal (stated) voltage...
Of course, if the SMPS is cheap and uses the wrong capacitors (not designed to handle high-frequency ripple), then.... blaming the SMPS, in general, would be quite unfair.
But I have never experienced a catastrophic failure as you described... usually, they just start oscillating at a lower frequency, which is (reasonably) easy to tell because they start to make a low pitched whine... and then you just replace them.
The really good thing about SMPS in audio is that they provide a very low and constant impedance across the full audio range, and then some.... This is not easy to achieve with linear power supplies and large capacitors.... here, you need to play a bit with the additional caps in the range of 0.1uF to around 1 -100uF... to get the same result. Also, when you place these additional decoupling caps, the end result (low impedance) is highly dependable on the distance where you place the cap, as well as on the wire thickness (or PCB track length & width). On this note, every power supply should have a 1uF cap somewhere, as a decoupling cap; it seems that "1" is a magical number here.
Many people just go from tens of thousands of uF's, to 0.1uF.... and poor little 1uF always get skipped.
Of course, if the SMPS is cheap and uses the wrong capacitors (not designed to handle high-frequency ripple), then.... blaming the SMPS, in general, would be quite unfair.
But I have never experienced a catastrophic failure as you described... usually, they just start oscillating at a lower frequency, which is (reasonably) easy to tell because they start to make a low pitched whine... and then you just replace them.
The really good thing about SMPS in audio is that they provide a very low and constant impedance across the full audio range, and then some.... This is not easy to achieve with linear power supplies and large capacitors.... here, you need to play a bit with the additional caps in the range of 0.1uF to around 1 -100uF... to get the same result. Also, when you place these additional decoupling caps, the end result (low impedance) is highly dependable on the distance where you place the cap, as well as on the wire thickness (or PCB track length & width). On this note, every power supply should have a 1uF cap somewhere, as a decoupling cap; it seems that "1" is a magical number here.
Many people just go from tens of thousands of uF's, to 0.1uF.... and poor little 1uF always get skipped.
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My head hurts.... I think I know what you are asking...
The same principles apply to both types of power supplies, of course.
It's just that with the linear power supply, we get the largest, lowest impedance capacitors available a priori, believing that this will improve settling time or lower peak overshoot (or both!), at all desired frequencies.
The above is hit and miss; an orthodox approach that is usually more of a miss.
With SMPS, I can get to the desired value (fast response/settling at all audible frequencies) much easier. Also, I can position them (SMPS bricks) much closer to where they need to be, which minimises the influence of wiring on this tunning process.
With linear power supplies, we have a necessity of accommodating large capacitor banks, to filter much lower frequency ripple -> which usually means positioning them further away.
Also, the recent SMPS I used (MeanWell) are really good; they need very little attention. I find that I spend much more time tunning the linear power supply, to make it sound good -> fast at both frequency extremes.
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"Hand-built, adjusted & optimised by Mr Pass".... of Pass Labs -> impressive.
In these power supply discussions, the question I have not seen addressed before ... would this or one of the offspring amps benefit from a dual mono PSU - meaning the use of two Meanwell 36V bricks, one for each channel ?
Using same or lower wattage rating if there's two of them ?
Best regards, Claas
Using same or lower wattage rating if there's two of them ?
Best regards, Claas
Despite the chassis with the kit costing more than the VFet parts alone (after shipping cost), I do feel they're more valuable together than separate. So I bit the bullet and chose it all. Consider that this chassis is unique to the VFet project and could only add to it's value if you somehow sell in the long term future. I've been approached in the past on buying "somebody's DIY project" but it just doesn't feel the same nor command that kind of pricing. The intrinsic value will always be the VFets alone ; as we've seen many salvaging old Sony VFet amps from the 70s and 80s.
Perhaps you're going with individual personality and nothing wrong using a different chassis - after all this is DIY!