SMPS Switching Mode Power Supply for symmetrical PSU ?
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chilidawg
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Simple advice: don't sweat the small stuff.
Good SMPS usually don't need an additional LC filter, or a linear regulator at its output.
I don't see anyone complain about SSL XLogic Alpha Channel being noisy, even though it has a cheap low quality switching power supply inside. How do I know? because I repaired a couple of them not long ago. They all died from the same problem. Dried CrapXin electrolytics on the primary and secondary, which eventually blew up the TOP controller IC, the rectifier and the main fuse.
Good SMPS usually don't need an additional LC filter, or a linear regulator at its output.
I don't see anyone complain about SSL XLogic Alpha Channel being noisy, even though it has a cheap low quality switching power supply inside. How do I know? because I repaired a couple of them not long ago. They all died from the same problem. Dried CrapXin electrolytics on the primary and secondary, which eventually blew up the TOP controller IC, the rectifier and the main fuse.
There should be a spcification regarding minimum load; it's for DC load, i.e. resistive. Many recent smps specify "no minimum load", though.
Now there is also often a specified maximum capacitive load, typically about 500-1000uF per nominal Amp.
Hi all ! Wanted to thank you 
The hum in my GSSL is gone now, I replaced the PSU with 2 meanwell 15VDC SMPS to a tiny board with two 1000uF cap and 7815 and 7915, no choke for the moment... Feeding the GSSL PSU with a clean and silenced +/-15VDC right after where the original regulator were. Super happy. (12VDC for the relay bypass and lights is provided by a small regular transformer stuck in a corner and it's silent so...
I had to adjust the negative SMPS unit output voltage while monitoring the -15VDC with a scope and ended up where it was the cleanest, and that's around 15.4VDC output for some reason. The positive rail is super clean, and maxed out to approx 19VDC before the regulator.
Now I'll have to port this to my API summing mixer, 2520 makeup amps for passive EQs, and upgraded DBX118
The hum in my GSSL is gone now, I replaced the PSU with 2 meanwell 15VDC SMPS to a tiny board with two 1000uF cap and 7815 and 7915, no choke for the moment... Feeding the GSSL PSU with a clean and silenced +/-15VDC right after where the original regulator were. Super happy. (12VDC for the relay bypass and lights is provided by a small regular transformer stuck in a corner and it's silent so...
I had to adjust the negative SMPS unit output voltage while monitoring the -15VDC with a scope and ended up where it was the cleanest, and that's around 15.4VDC output for some reason. The positive rail is super clean, and maxed out to approx 19VDC before the regulator.
Now I'll have to port this to my API summing mixer, 2520 makeup amps for passive EQs, and upgraded DBX118
