Connex vs. Meanwell 48V SMPS for TPA3255 based amp

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avivz

Member
Joined 2004
#1
Are there any solid opinions or meassurements on Connex PS vs. Mean Well ?
For example, SMPS300RS vs. MSP/SE/LRS series?

Mean Well is a respected company and have great products in general. I have no experience with the Connex, but they claim to be superb for audio applications. on paper, the Connext has less than half ripple voltage than the Meanwells. However, line and load regulation figures are not mentioned for the Connex.

In tems of components or construction quality I can't say much, as I don't have them in hand. Connext are more expansive.

Any advice?
 
#3
Connex are regulated. Its strange that they don't specify load and regulation as these should be good if regulation works well.

Connex seem to have a more sophisticated design. I own and use one SMPS300RS and it behaves very good. Product seem well built.

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#5
I just purchased two of the Meanwell UHP-500-48 supplies. These are a step up from e.g. the LRS series equivalent. They are fanless (but need to be mounted to a chassis to do 500W continuously) and have a universal power supply with power factor correction. They do cost more, but for me it is worth it for the extra features and the fact that it has sufficient power rating for using the TPA3255 2ch into 4 Ohms.
 
#6
Looking in the datasheets, the UHP has some advantages like active PF correction, fanless. however, on the other hand its max ripple is 360mV p-p, which is significantly higher than the 200mV p-p ripple of the LRS-350 or the SE-450. the MTBF of the UHP is also lower, so I wander what makes it a better choise.

Did you consider these points?
 
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#7
symmetric power supply?

Are there any symmetric smps from Meanwell to create e.g. +-48V?

Could not find any on their web page.
And I don't know how to connect them in series as the output is not floating (apart from the IRM series but these are limited in power) and the negative output is connected to ground.

But Neurochrome has done it and you can buy a PCB form him:
Mean Well Control: Power Your Audio Amp with Mean Well EPP or RPS SMPS – Neurochrome

Any idea what is behind this PCB?
 
#8
The RSP series for example, when comes in PCB style (no enclosure) is suitable for class II (no FG) applications. I assume in that case the output is floating and therefore can be used in a symmetric configuration. Mean Well datasheet provides a hint.
I’m not sure exactly what this control PCB gives, probably just one control and indication for both supplies so they can be seen as one. It does not look like it floats the outpus by some magic.
 
#11
Aviv said:
Looking in the datasheets, the UHP has some advantages like active PF correction, fanless. however, on the other hand its max ripple is 360mV p-p, which is significantly higher than the 200mV p-p ripple of the LRS-350 or the SE-450. the MTBF of the UHP is also lower, so I wander what makes it a better choise.

Did you consider these points?
Click to expand...

Switching frequency ripple is not going to pose the same kind of problem as the more familiar 2x mains frequency ripple that is produced by a linear power supply, when we are talking about the TPA3255. There is a TI app note about this:
https://www.tij.co.jp/jp/lit/pdf/slea049

A quote from the app note:
If a switch-mode power supply (SMPS) is used, there is no 100/120 Hz ripple voltage, but there can be a switching-frequency ripple voltage. This is normally well above the audio band and low-amplitude (less than 100 mV); therefore, no audible tones are produced. Figure 2 shows the FFT.
Click to expand...

So I don't worry about it. The other features of the Meanwell UHP supply are more important to me, to meet my particular needs.
 
#12
joe said:
Are there any symmetric smps from Meanwell to create e.g. +-48V?

Could not find any on their web page.
And I don't know how to connect them in series as the output is not floating (apart from the IRM series but these are limited in power) and the negative output is connected to ground.

But Neurochrome has done it and you can buy a PCB form him:
Mean Well Control: Power Your Audio Amp with Mean Well EPP or RPS SMPS – Neurochrome

Any idea what is behind this PCB?
Click to expand...

I wired in series 2 LRS-200-24 and they worked flawlessly as a symmetrical PSU (+/- 24V). No special connection, just wires. With that ripple at 20Mhz you don't need extra filters, my amps are dead silent, no hiss, no hum, no nothing. Sometimes protections diodes are required, but most of the Meanwell PSUs already have them ant the outputs are floating with no common GND. I can't see the point for the controller in that link.

I'm not going back to big transformers.

I've done this with multiple kinds of supplies, most of them worked. Here is a hint: if you want to try wiring smps in series and you don't know much about them, use protection diodes across the outputs and for the first run use a very thin wire for interconect (+ of the first smps with - of the second one) - this way, if there is unwanted current, the wire will burn leaving everything save.
 
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#16
I always fix a broken fuse by dropping a small wire with the same thickness or more along the inside.

Come on, it is just a safety measure. :zombie:
Normally I try to have equipment without a fuse.

here in this case the loose wire can be used without a glass surrounding it (e.g. 2 cm long, bare wire, taken from a strand of standard wire).
 
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