icepower 500A Project

[Nikon1975]

Dear All,

I was thinking to give a last chance to my power hungry speakers before going a different direction.
An easy way would be to put together an amp using Icepower modules. I was targeting the 500A as I have a transformer that may suit.
The idea would be to go with a CRC power supply.
Here is my confusion: I find in the documentation the data on the quiescent current, but no useful info on the power requirements.
First question is:
1) My transformer has two secondaries: 45V 13.2A and 50VCT 8.8A

Would it be enough ? The voltage after rectification would be 62VDC and 72VDC respectively. My speaker are low impedance so they need current rather than voltage.

What are the power requirement for the +-12V?

Thanks,

Davide

 

[coolnose]

Application note

Davide,

this might help a little.

https://www.google.fr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0ahUKEwizivSgvJfKAhXKchQKHaxnAt0QFggvMAQ&url=http%3A%2F%2Fwww.icepower.bang-olufsen.com%2Ffiles%2Fsolutions%2Ficepower500adata.pdf&usg=AFQjCNFP9kBPxonOd9SJNE3nYWk8qsjmPw&bvm=bv.110151844,d.d24&cad=rja

CRC should do fine, I remember seeing an application note (can't find it right now) showing Bridge rectifier + plain C of min. 10KuF per Rail as minimum requirement.

Cheers,

Max

 

[Nikon1975]

I read already this file and it speaks of mA of current, while I see people using 500VA transformers

D

 

[Nisbeth]

The +/-12V power supply needs to be around +/-200mA or higher. The high-voltage supply (Vp) needs to be max. 80VDC and power requirement is from 3-400VA up (the transformer that was supplied with the original EVM was 400VA).

Using a CRC-supply for Vp is a bit pointless, a) because ripple rejection on this rail is very good and b) because you want a low-impedance supply here. If you want to optimise the quality use large caps but not CRC for Vp and then focus on providing low-noise supplies for +/-12V where is really matters.

/U.

 

[coolnose]

Davide,

I stumbled across this short thread... that might help with you calculations.


http://www.diyaudio.com/forums/class-d/231502-choosing-transformer-va-icepower-500a-into-scintilla.html

Max

 

[Nikon1975]

Is there any penalty on using a lower rail voltage, like the one I would have ?

Nisbeth, I agree and using a C only PSU will make things even easier.

I want to give this technology a try without investing too much, that's why I want to use what I have.

Thanks,

Davide

 

[Nisbeth]

This is worth a read as well BTW: Understanding Class-D amplifier power supply requirements | EE Times

/U.

 

[Nisbeth]

Is there any penalty on using a lower rail voltage, like the one I would have ?

Only a reduced max. output power. However, this is of course the voltage-limit which you might not even hit if you have low-impedance speakers.

/U.

PS: Be aware that the A-series modules don't have current limiters so a short will likely kill them.

 

[Nikon1975]

Thanks,

I am aware of that, also my Class A amps do not have current limiters.

D.