Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects

Construction information for DIY projects, including the MS Mid Side Matrix, Elliptic Equalizer, Mastering Console, Phono Transfer System, Insert Switcher and the Dual Class-A Amplifier. You can post your baby pictures here.
emrr
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Re: Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects

Post by emrr »

Further tests are showing the 13k5 and 19k2 bumps to be environmental. Perhaps the 240 you see is too.
Best,

Doug Williams
Electromagnetic Radiation Recorders
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mediatechnology
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Meanwell LRS-50-24 24V 50W For Insert Switcher Relay Supplies

Post by mediatechnology »

Wanted to add the Meanwell 24V 50W supply for Insert Switcher builds.

https://www.mouser.com/ProductDetail/709-LRS50-24
Fragletrollet
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Re: Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects

Post by Fragletrollet »

Hello!

Planning a console build using 2x IGFO, 4x insert switcher, 1xMSII and 1xEEQ. Browsing options from MeanWell, how many amps are needed for these boards? Are the mA stated in the build docs (for all except the Insert Switcher) with all relays energized, aka total draw?
I know my additional LED's, meters & illuminated buttons will have to be added. Something like RS-50-25 or LRS-75-24 for the relays/led's, and a couple of RS 1515 or LRS 2515 for the bipolar 15v rails (I presume this works with these supplies, aka psu1 V+ = 15V, psu1 V-=0V, psu2 V+=0V and psu2 V-=-15V. I see that V- is connected to main earth, but through caps and other parts so I'm thinking it would be OK to connect it like explained?) or RS2524's for bipolar +/-18V?

I see RS has a little lower ripple than LRS, so I should choose RS?

Or maybe go for a RT-65C instead (is 0.5 enough Amps on the negative 15v?)?

I don't have much experience with SMPS, but was thinking to run these into something like a couple of TREX (TIP122/126 + caps & trimmer) for some conditioning of the bipolar audio rails between the supply and boards.

How does this all compare to just getting a suitable dual tapped 15V trafo and running it into a linear supply?


Thanks for any input and all the best,

Magnus
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mediatechnology
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Re: Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects

Post by mediatechnology »

Magnus -

The currents given in the build documents are for the bipolar rails only.

I would highly recommend the TDK CUT35-5FF for the audio supply.
Mouser's delivery is in May of 2022 but Digi-Key have them. https://www.digikey.com/en/products/det ... FF/6874071
The /A and /B versions are the cover and base plate versions.
https://product.tdk.com/en/system/files ... ut35_e.pdf

Don't forget to buy JST connectors and pins. They are in the BOM for the TDK post. viewtopic.php?f=7&t=945

The 1A (+) and 0.65A (-) capability will offer plenty of extra current.

Your boards use 24V relays for everything except the Insert Switcher which use 12V relays in series for a 24V coil.
The 24V Omron relays in the BOM pull about 8.3mA each.
Add 10 mA for each LED.

The Insert Switcher relays are 12V. In Omron the current is 12.5 mA.
There are 14 relays on each board but because they are in series they count as 7 at 12.3 mA.
Add 3 LEDs (max) per board at 10 mA.
For 4X insert boards with all relays engaged you're looking at about 0.46A.

Based on the number of boards it look like they relay supply will need about 750 mA or 18W.
I'd use the 50W Meanwell which will give you quite a bit of extra headroom though you could use a 25W if you needed too.
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mediatechnology
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Re: Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects

Post by mediatechnology »

mediatechnology wrote: Thu Mar 29, 2018 7:23 am The following oscillograms show why I recommend the discontinued Meanwell P25A over the replacement GP25A. Both supplies had thier 5V outputs loaded in the minimum 500 mA. The 30V load was light IIRC about 50 mA.

The top image is the GP25A. The upper trace the +15V output the bottom is the -15V rail.

Image
Meanwell GP25A14E-R1B Ripple

The discontinued P25A has far lower ripple and noise.

Image
Meanwell P25A14E-R1B Ripple

The DSO is sampling at 25 kS/s to show the LF ripple. The GP25A's HF ripple is just as ugly.

The previous FFTs were the output of a board powered by both the P25A and GP25A. The PSSR ratio of the onboard devices is pretty good at LF but out-of-band HF response does show degradation with the GP25A.
I had a chance to test an EljinTek GPSN25 +/-16V unit. (No 5V output.)

https://www.eljintek.com.tw/propdf.php? ... _1708C0CD4
This unit is available with a +48V output option and I think this is the unit JLM once sold.

I believe that EljinTek make the Meanwell GP25A and I recall an earlier Meanwell P25A unit actually having EljinTek's name on it.

As it turns out an unloaded GPSN25 has the same ripple on the +16V line as the Meanwell GP25A shown quoted above.

I discovered that the GPSN25 needs at least 100 mA load, rail to rail, to come out of hiccup mode. I used 300Ω from the +16 to -16V rail.

There is no third rail to pre-load in this model.
Once pre-loaded there's still some HF ripple that could easily be post-filtered.
I need to connect it to a board and compare FFTs.

It occurred to me that I should have loaded the Meanwell GP25A differentially, i.e. rail-to-rail, when I tested it.
I didn't.

Since the EljinTek and Meanwell appear identical I decided to re-evaluate the Meanwell GP25A.
Sure enough the GP25A comes out of hiccup mode at 100 mA.

I does appear however that the HF ripple is still higher than the EljinTek leading me to conclude the EljinTek has better output filter components or additional stages.
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