Need help with transformer specs

Hello,

I need some help specifying a transformer. It will be used to power a music server. The idea is to use a dual winding transformer, and feed one of the secondaries into an Evotronix single active power supply (seen at the bottom of this page). I attached a schematic of the circuit. This will in turn feed unregulated power to an HDPlex 400W DC-ATX converter that will power the motherboard and CPU. The HDPlex accepts input voltage of 16-30Vdc.

The other secondary will feed into an Evotronix Zeno MKII linear power supply, which will power a network card that accepts 5V 2A. I attached a schematic of the Zeno MKII as well.

The single active power supply uses a FWB rectifier with input cap, so I think I understand peak DC voltage will be 1.414 X Vac at zero load and before diode voltage drop. Where I'm confused is how current will be affected. The Hammond rectifier design guide says DC current will be .62 X the secondary AC current. Say I have a 20Vac 10A secondary. After feeding it through the single active power supply, will I get 28.28Vdc 6.2A? I would like to supply the HDPlex with 20-28Vdc 10A. Would I need a secondary rated at 16A (10/.62=16.129)?

On to the other secondary. The Zeno MKII looks like it uses a half wave rectifier. The Hammond guide says DC current is .28 X the secondary AC current for this load. The goal is 5Vdc 2A to power the network card. Would this secondary need to be rated at 7A (2/.28=7.14)? The Zeno is rated up to 4A continuous, so would this cause any issues?

FWIW, estimated power consumption of this server under load is 200-220W. I've also read computers represent a non-linear load with lots of instantaneous peaks, which confuses me even more.

Sorry if I posted this in the wrong section. I'm not very knowledgeable about circuits but would like to learn. Thanks for the help.
 

Attachments

  • PS_Server-1.jpg
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  • ZenoMKII.png
    ZenoMKII.png
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Hi ,why do you chose linear power supplies for things on Iike server or pc ? Those are fine with smps , and you will have less heat and power consumption . Linear needed only when directly related to audio - preamplifier , dac ,adc ...