is current in speaker load to be anyway closer to psu current ratings? - Page 6

AndrewT · 10th December 2012, 09:50 AM

Forget about trying to determine transformer current from amplifier current.

The connection from one to the other is very complex. Look at Goottee's Thread for just how complex.

If you can get beyond that complexity and think about what the transformer rating is:
The VA rating, from which we can extract the current rating, ONLY applies when the transformer is feeding AC current to a purely resistive load.

That is NOT what happens when you rectify and smooth the output of a transformer.

Stay with the simple determination. VA~1.5times total maximum power.
Then measure the resulting ripple on the smoothing capacitors and decide if that meets your target for amplifier performance. Adjust if you are not happy.

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10th December 2012, 09:50 AM	#51
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Forget about trying to determine transformer current from amplifier current. The connection from one to the other is very complex. Look at Goottee's Thread for just how complex. If you can get beyond that complexity and think about what the transformer rating is: The VA rating, from which we can extract the current rating, ONLY applies when the transformer is feeding AC current to a purely resistive load. That is NOT what happens when you rectify and smooth the output of a transformer. Stay with the simple determination. VA~1.5times total maximum power. Then measure the resulting ripple on the smoothing capacitors and decide if that meets your target for amplifier performance. Adjust if you are not happy.