Switched Mode Power Supplies (SMPS)

[alkasar]

Originally Posted by SoldierAnt76

A 200-300 watt, single-voltage SMPS would be a fantastic idea if it cost significantly less than its 500 watt cousin. However, since the least expensive Connex SMPS is $50/40€, I wonder whether the price would be all that much lower. The Meanwell S-350 will still win on cost per watt at $30, and if you're paying extra for a Connex supply you might as well pay a bit more for the additional headroom.

But yeah, a package deal would be a great way to get this SMPS into the hands of more of Hifimediy's users. Or maybe a link on his webpage would be enough.

main meanwell issue is size ! it is incredibly reliable and cheap ($40 retail) but many would pay some extra to fit in 1U box size and have a built-in aux 12V.
IMHO, there is a demand on two segments :
250-300W 24-30V low cost, small form factor, for the tk2050 stereo amps.
600-1000W 30V-48V for multichannel amps with multiple tk2050 boards.

[TCx]

I prefer quality over cost too. And agree that the main issue is size.

I think that high watt needs are quite well covered by existing models of SMPS' as they can be probably slightly modified to provide single voltage main output. Maybe they can be used as they are - using only positive and negative terminals, leaving GND terminal unused. Only the dual voltage would have to be reduced to let's say +-15 to +-24V, to provide single 30V and 48V. But I am not sure if the existing SMPS' can work with siginificantly higher currents if the voltage decreases while the power should stay the same.
Maybe it is not necessary to design so many new SMPS' with small differences in output power, as their production costs would be probably very similar anyway. Maybe 100+W and 250+W would cover most situations.

But again, I am thinking loud and maybe I miss something important...

[SoldierAnt76]

I pulled the trigger and bought a SMPS500R-Single for my TK2050 amplifier. Sure, I don't need 500 watts, but I doubt a ~300 watt version would be all that cheaper. And the small size is nice.

I agree that quality is the best way to compete with the cheap Meanwell clones. People will pay a premium for performance, which is why Hifimediy and Arjen Helder can charge more for their products.

But quality isn't self-evident, so you might want to stress that Connex power supplies are specifically designed for DIY audio. I suspect most people use Meanwell knockoffs simply because there's nothing better available.

[Cristi]

Originally Posted by alkasar

main meanwell issue is size ! it is incredibly reliable and cheap ($40 retail)

the low price and relative reliability comes with low efficiency, around 75-80% for most of them and bulky size and shape.

Originally Posted by alkasar

IMHO, there is a demand on two segments :
250-300W 24-30V low cost, small form factor, for the tk2050 stereo amps.
600-1000W 30V-48V for multichannel amps with multiple tk2050 boards.

i will consider all the suggestions and focus towards designing a better, cheaper and smaller size, more compact product for a given power range.

Originally Posted by SoldierAnt76

I suspect most people use Meanwell knockoffs simply because there's nothing better available.

there are many other companies which are able to develop and produce high quality smps's for audio, see hypex for example. they have few smps models, but, i think, they don't concentrate on this aspect more probably because is not worthed for them to invest time and money to develop and produce other models than they have, knowing that the audio smps market is a very small ultra-tiny niche where is quite hard to recover the investment, not to mention making profit. a 500W smps has more components than a classD amplifier module with the same output power, and the BOM cost can easily reach double the price the BOM of an amplifier, same power.
as an example, the power transistors which i use for SMPS2000R cost 14.5 euro each at digikey. is the only place i can buy them in small quantity, 50-100 pcs at reasonable price and guaranteed quality. of course if i would have to make 10000 pcs "meanwell" i could find other sources for parts and the decimal dot of the price could shift one character to left. that's just one of the secrets of the low price of that smps's.

[Cristi]

SMPS500R manual available: Connexelectronic
Connexelectronic
http://www.connexelectronic.com/documents/SMPS500R.pdf

[glt]

Hello Cristi, thanks for all the information and the great products you provide. I am still looking at a good smps for my hypex modules (and I am one of those that would not mind paying more for better quality)

I suppose for Audio applications (as opposed to general purpose) one has to pay more attention at filtering the high frequency noise generated by the electronics in the power supply. In addition, there is efficiency and power factor. I don't know how the latter two are related to audio applications.

Can you share with us those areas that makes your smps good for Audio applications? And also, what improvements can be made? For example, in linear supplies larger output caps seem to be a preferred approach for good audio supplies. Thanks...

[SoldierAnt76]

Originally Posted by glt

Can you share with us those areas that makes your smps good for Audio applications? And also, what improvements can be made? For example, in linear supplies larger output caps seem to be a preferred approach for good audio supplies. Thanks...

Along the same lines, what are the advantages of dual voltage versus single voltage? I notice your amplifiers require +/- voltages, while other Tripath amps are built for single voltage. I also see the single voltage SMPS500R has a larger heat sink than its dual voltage cousin - is heat dissipation a factor?

[glt]

Why these SMPSes are good for audio is explained in the manual: http://www.connexelectronic.com/documents/SMPS500R.pdf
Summary:
1- Soft switching
2- Lower EMI
3- Regulated (constant voltage independent of load) -I thought all SMPSes are regulated
4- High Efficiency (not sure how this would relate to audio)

One question on voltage: I want to use it for the Hypex 180. The spec says 50V max, so the +/- 54V model seems a good fit. I would probably set it at the minimum Vout of 48V. How close to 48V can it be adjusted?

Thanks.

[Cristi]

Besides the stock output voltages, i could provide any output voltage in range of +-20V to +-150V for any SMPS. the differences are few. first, the transformer secondary number of turns, then the voltage divider resistors from the feedback loop. also, the rectifier diodes maximum reverse voltage, which should be higher than the sum of the output voltages.
In your case, i could provide a SMPS with output voltage adjustable within +-45 to +-54V.

[SoldierAnt76]

Out of curiosity, how do you set the auxiliary voltage on the SMPS500R-Single?