Impulse wall socket power supply typical schematic and upgrade

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Hi! Nubie question from oldschool electrican 

I have wery unstable mains (random voltage from 180 to 230V) and I`m looking now for bunch of impulse power supplies (9)12V 2A with wide input range
(See varians in attachments)

What about typical schematics, ripple voltage, hum etc.? Can I tweak this unit to other output voltage without rewinding transformer?

Thanks!

PS: Sorry for my english

[ebclr]

Tipically this is inside those box