Yes can confirm, but in PA appliaction all BRANDS have problem and fail.
Some American brands using exotic semiconductor power parts,
OBSOLETE impossibile to fix, 5 - 7 years old amp
QSC Powerlight 9 was N-Channel Mosfet amp with +/- 200V DC Rail
If QSC not have problem with SMPS, they never discontinued Powerlight 9
A big company cant solve SMPS Problem......
Powerlight 9 with transformer could be a workhorse, but never build.
Transformer Powerlight 9 N-Channel Mosfet amp
would show every Class D amplifier who is the boss in the house.
There is no Class D amplifier that can outperform a Powerlight 9
SMPS are widely used in industrial controls, semi-conductor ATE, defense electronics, etc where down time has catastrophic implications to bottom line manufacturing cost or readiness - they are reliable.
In the local Boston area there are a plethora of SMPS manufacturers like Vicor with SMPS with rated MTBF of up to a million hours. I've never seen any of these converters fail in use and they sometimes turn up surplus or used on eBay and at local hamfests. I've never had an instance of one not working even after a long commercial life.
TI makes a line of switcher modules which have become something of a standard in high reliability applications. Murata makes good DC to DC converters (a bit noisy - use filters)
In the local Boston area there are a plethora of SMPS manufacturers like Vicor with SMPS with rated MTBF of up to a million hours. I've never seen any of these converters fail in use and they sometimes turn up surplus or used on eBay and at local hamfests. I've never had an instance of one not working even after a long commercial life.
TI makes a line of switcher modules which have become something of a standard in high reliability applications. Murata makes good DC to DC converters (a bit noisy - use filters)
No argument here, but for cost/weight/space savings many would take the risk.
For consumer and DIY it's a definite win IMO.
When you working since 2006 in Sales, you can see what Brands and models fail and comes back from costumer to service.
For Brand Amp > 1000 EUR / USD I expect rugged reliability and not fail.
When up to 10 - 25 % fail within 3 to 5 years
If 10 - 25 % cheap Chinese junk fail similar Behringer fail, its ok, but not for an expensive branded device
Yes I believe it, but SMPS in PRO Audio I cant confirm
Same problem have DC Inverter Air Conditioner after 2 -3 years SMPS fail.
No way to fix.....300 EUR / USD for new PCB please
PA Amplifier
up to 25% fail within 2 - 5 years after purchase is a no go .
Expensive Brands fail, this is a no go, there is no big differennce in reliability
compare to cheap chinese junk only the price i
Not only in PA
DC Inverter Air Conditioner same 2 - 5 years after purchase SMPS fail
Mil and Industry I will believe SMPS are reliable,....
I own a 1998 Peavey CS800s with switcher supply that failed about 2014. A 22 uf electrolytic failed and took out the feed resistor. This was in the power supply to the switcher control IC. Replaced the mains caps while I was at it. I'm not trying to repair cheaper than the tech down the street. I'd say 16 year run is pretty good. You have any of CS800s blow power supply in 3 to 5 years? They are not cheap. Peavey has readily available schematics. This amp came in 2010 with blown input resistors; Peavey uses 1/10 watt resistors to burn up if someone plugs a 75 W guitar amp in the input jack. hard to read the value on cinders, glad there was a schematic.
I repaired a 1999 Allen organ switcher supply in 2017 that had blown. Mains filter caps had gotten leaky, blew a NTCR they were using as a mains fuse. I'd say 18 years is a good run. Those organs are not cheap, start at about $30000 I believe.
Allen copywrites their schematics, I fixed this supply without one.
The market drives the demand for trash. Behringer equipment not working is all over craigslist (internet market), I look down my nose at them. Mackie mixer+amps & Bose power speakers, too. Those brands outsell Peavey 20 to 1 I imagine. Don't know that Peavey maintained the standard into the 2010's, I haven't worked on a recent product.
As for the wall-supplies, I loaded up on the transformer versions when charity resale had a shopping cart full for $1 each. Switcher wall supplies? Belong to the throw away 21st century. The whole ROHS legal disaster was caused by 1 year life computer displays polluting landfills with lead, IMHO. Im using a 20 year old phillips CRT display that works fine, switchers can be done correctly.
Last edited:
Switchers drive the caps hard, particularly at start up. The desire to keep things small and cheap exacerbates this.
How does a buyer know? You bring home the latest widget and it's so cute & small & light, how are you to know the designer didn't extend those parameters to include CHEAP? Power supplies are often an afterthought, and subcontracted to the lowest bidder.
My latest AV receiver is rated 105W x 7 and has a baseball-sized transformer.
At moderately-loud volumes you can't hold your hand on the cover. I don't expect a long life out of it. I'd have much more confidence if it had paralleled output transistors for each channel, EXTERNAL heat sinks, and a 20# toroidal transformer.
Like my 1982 system downstairs that's never needed service.
I have worked in commercial avionics for over 30 years; cockpit displays, GPS and SATCOM. Switching power supplies are the norm; especially for general aviation (Gulfstreams, Cessna Citations, Falcons some helicopters etc.) since they typically do not have 115V/400Hz relying mainly on 28VDC for the main power bus. Switching power supplies are ubiquitous and very reliable.
Even in aircraft with AC busses (passenger jets) switchers are very common. They can be made very efficient; can have power factor correction, low harmonic currents reflected on to the line and are more readily made tolerant to brownouts/bus switching transients.
Like any kind of design; you have to allow for margins in operating voltage/current and temperature. This is easily done without resorting to military components (which are getting more and more difficult to get anyways).
Even in aircraft with AC busses (passenger jets) switchers are very common. They can be made very efficient; can have power factor correction, low harmonic currents reflected on to the line and are more readily made tolerant to brownouts/bus switching transients.
Like any kind of design; you have to allow for margins in operating voltage/current and temperature. This is easily done without resorting to military components (which are getting more and more difficult to get anyways).
I don’t think there is any question that a SMPS can be reliable, pretty much every computer system in the world uses one. Of course like any other product you can get good and bad switching supplies. I try to avoid the no name stuff from China and stick to known brands such as Meanwell or TDK/Lamda.
I lately have started to see Mean Well switching power supplies on demanding 24/7 industrial and building automation duties. I had to replace several failed ones already. Reliability seems to be much better on latest low to medium power designs: switching and control are integrated on the same IC, with fewer discrete external parts compared to the previous designs with discrete MOSFET. As power increases, the cost of a good SMPS power supply is higher than a traditional linear power supply with toroidal transformer. For instance: the least expensive 12V 1000W SMPS power supply I am considering for a industrial design I'm working on does cost 250 euro + tax; the TDK-Lambda alternative (7 years warranty) does cost almost 400 euro, and this is not even the best or most expensive one. Compare this to 60-70 euro for a generic consumer quality SMPS of the same nominal specifications sold on popular ecommerce web sites; basically the one you will find inside a standard amplifier today. It is no wonder that SMPS have a bad reputation.
By that time it is written off anyways and who rents a more than five year old amp these days??
Okay ...
First they provide a very clean, well regulated output that is a real advantage over the unregulated outputs that most linear supplies provide to audio output stages. Consider how much better an amp would perform if the output rails didn't sag at high power.
Second, they do not hum. The output of an SMPS is refreshed roughly 50,000 times a second, vs the 120 hz refresh for linear supplies. A simple test is to hook up an amplifier with one speaker and a dummy load on the other channel... Feed audio into the channel with the dummy load... What do you hear from the speaker? With a liner supply you will hear a 120hz hum modulated in amplitude by the music. On an SMPS you will most likely hear nothing.
Third, they are more efficient. Linear supplies get up to 40% if you're lucky. SMPS manages to convert up to 90% of input energy into output energy.
Fourth, they are smaller and lighter. Take a look at the new breed of Class D amps with switching supplies... The Crown XLS1002, for example, produces over 300 watts per channel but weighs only 13 pounds... 20 years ago that kind of power would have been so heavy it would take 2 people to move it.
Fifth, unlike linear supplies, SMPS are generally designed to be left powered up all the time, thus reducing the repeated insurges of current that can destroy rectifier bridges. In fact, their lifetimes are shortened by repeatedly turning them on and off.
Your comment took me back 35 years to when I had a Dynaco Stereo 120. It has a single-ended regulated supply and big electrolytic blocking caps on the outputs. One day I became aware it was sounding much better than normal. Tighter imaging, more detail. It also had a slight increase in hum noticable when there was no input. After a week or 2 I opened it up and discovered the series regulator transistor had shorted out, passing the full unregulated rail voltage to the output transistors.
Fixing it brought back the flat sound I was used to.
Does lower output impedance in a power supply "sound better"?
The ST120 had a problem with low output transistor idle current under some conditions, like soft. They had some crossover distortion. More rail voltage may have resulted in more idle current, which would improve the distortion. As they often blew up output transistors, a risky procedure.
I own one. Djoffe designed a 7 transistor circuit to control the idle bias current with a feedback loop. It works, I'm listening to it now. Tends to blow up 2n3904 sense transistors, use ztx653. Dynaco Stereo 120...can be beautiful
TIP mod (see greg dunn website) helps too, TIP3055 or MJ15003 output transistors helped distortion a lot over 40636 originals. More questions post on thread above.
I also added 2 fans from PCAT supplies to cool the inadequate heat sinks. Runs 14 hours a day often, NTE60 OT's are now tens of thousands of hours old.
I own one. Djoffe designed a 7 transistor circuit to control the idle bias current with a feedback loop. It works, I'm listening to it now. Tends to blow up 2n3904 sense transistors, use ztx653. Dynaco Stereo 120...can be beautiful
TIP mod (see greg dunn website) helps too, TIP3055 or MJ15003 output transistors helped distortion a lot over 40636 originals. More questions post on thread above.
I also added 2 fans from PCAT supplies to cool the inadequate heat sinks. Runs 14 hours a day often, NTE60 OT's are now tens of thousands of hours old.
Last edited:
Usually ... the ability to provide DC at fixed, unwavering, voltages is a definite advantage.
I have several 70 yr old amps that will knock a lot of spots off modern ones.
They are going perfectly fine after all those years.
I also have a pair of 55yr old amps I use daily, that sound absolutely fantastic.
There is nothing you can buy I have heard that sounds even remotely close to as good as they do.
Perhaps the "kleenex" - "throw it in the bin" syndrome has meant people buy a bit of electronics like they do a car, expecting it to go to scrap in 5 yrs.
I routinely deal with old Jaguars that are often 50-60yrs old.
They usually work better than new.
Ie,- you get what you pay for.