Properly sizing transformers for Class D amps

[destroyer X]

Richie boy, thank you, informations are welcome here.

Thank you.

Carlos

 

[destroyer X]

I constructed a Peak power meter.

And amplifier measured 100 watts peak each channel...so, this can be something alike 60 watts each channel....a little bit less related the consumption (125 watts).

Now it is clear that really is efficient...produce power without too much heat... and have incredible dinamics.

Very good.

Carlos

 

[richie00boy]

You work fast, Carlos. Excellent job 🙂 To finish off you could construct another power meter to monitor the incoming power and see how close to that 125 watts you really are 🙂

 

[destroyer X]

Not so precise...meter needle weigth...this is not so good

So, in the reality, you can reduce 20 percent the power measured, so, will reach the 80 percent normal efficiency.

Dinamics are wonderfull....distortion is reasonable with volume all the way up.

But have not AC ampere meter....maybe in the future, opening enclosure, i will check voltage and current both rails to calculate the consumption reflected in transformer primary.

Go ahead with supply, thank you and sorry to scape, just a little, the main thread subject.

Please...go to the track again.

regards,

Carlos

 

[Yves Smolders]

Another power supply design question:

For UcD400's, what cable should I be using from the bridge to the caps/caps to modules? Is 2.5mm enough? multiple strands or massive cable?

3 days, and still waiting for hypex to ship... i'm sooooo curious... maybe i'll start the power supply design this weekend.

😀

 

[richie00boy]

2.5mm^2 cable is fine even running a pair of modules off one PSU. It's what I use at those currents. Stranded is my preference as it's easier to work with. As long as you keep things short (less than 14cm) you shouldn't have any problems.

 

[richie00boy]

Just a note to people searching for transformer sizing as per the original thread title, whilst my calculations and methodology throughout this thread are valid, my assumption of the average current drawn by a class-d amp was not. Thanks to a couple of posts by Jaka Racman in the "UcD180 questions" thread, I understand that the average current is less than that which would be for a class-b amp, therefore the transformer does not need to be as large.

A reasonable rule of thumb is that the class-d amp draws 0.68x the current of the class-b amp/load.