Look over my proposed build please

Hi guys

I'm looking to build my first class D amp for home hifi listening.

I intend on using 2x hypex UcD180HG amplifier modules. (46v)

I would like to use a linear power supply consisting of a Nuvotem Talema 230V ac, 48V ac Toroidal Transformer, 100VA 1 Output going into a Schottky Rectifier Filter Power Supply Board 120A DIY Sound Speakers 50V 10000UF, which will feed both amplifier modules

How far off am I guys? I know I have made errors which is why I would appreciate your knowledge and help.

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I wasn't able to find the data sheet for the UcD180HG. I suggest you request it from Hypex and read it. My comments below are based on the UcD180 OEM.

If you want ±46 V, you'll want to aim for about 2x34 VAC from the transformer, maybe even a bit lower. The reason being that the rectification and smoothing essentially works as a peak detector. 34 V RMS = 34*sqrt(2) = 48 V, peak. In reality you'll see some voltage drop across the rectifier and some voltage droop due to the ripple voltage, which is why I usually use a factor of 1.35 instead of sqrt(2)=1.41.

For ±46 V operation I'll use at least 63 V rated capacitors. Keep in mind that the mains voltage varies. ±10% is common. So suddenly your ±46 V exceeds ±50 V and your 50 V caps will get rather cranky. They might not explode right away but definite expect their lifespan to be reduced if they don't outright explode.

±46 V is a good target as the UcD180 is rated for ±50 V. It shuts down if the rail voltage exceeds ±56 V.

100 VA per channel is probably OK for music signal. I would not go any lower. If you can afford 200 VA per channel I think you'll end up liking that better. Keep in mind that the charging current pulses that go into the capacitors get pretty high when the amp delivers the full rated output power. That skews the RMS vs average current ratio, so often transformers are sized for something like 1.6*V*I. That gets you to about 300 VA for 180 W output, but you can undersize the transformer a bit as the amp will (presumably) be used for music reproduction. A factor of 3 is not unreasonable, but I would definitely not pushing beyond that.

Hope this helps.

Guys, thank you so much for the helpful replies.

100v rectifier it is.

Would I be correct in saying for the Schottky I would need a dual output toroidal? I.e 48-0-48v. The one I was looking at is single output.

Would anyone recommend a different pair (or 2ch single PCB) amplifier module(s) rather than the hypex I'm looking at? (Before I buy stuff) Focus being on sound quality rather than raw power. Budget <£200.

Thanks again :)