# Emotiva UPA-1 transformer modifications



## jackfish (Dec 27, 2006)

The Emotiva UPA-1 monoblock power amplifier uses a 300VA toroidal transformer and has 80,000 uF of secondary capacitance. With a pair of UPA-1s this is approximately equivalent to a 600VA toroidal transformer and 160,000 uF of secondary capacitance in a stereo amplifier. Would it be possible to swap in a 400VA or 600VA toroidal transformer into each UPA-1 without any other modifications or would other adjustments have to be made to utilize the larger transformers?


----------



## Anthony (Oct 5, 2006)

Hmm, interesting question. I am not a amp design expert, although I've built a couple of kits and played around with broken ones to see how they worked.

My understanding of power supplies is that the torroid is sized to not saturate under the high current draws being pulled from it. In this regard, it only needs to be sized to the max sustained pull of all the channels. The power supply caps are most important for storing charge for peak consumption (transients, louder passages, explosions, etc). That being said, I believe all the draw from the power supply goes through these caps, even if they are not "taxed" with heavy load.

So upgrading the torroid and not the caps may not have much effect. And if both are upgraded, it may not change much if the amplifier draw doesn't max out the power supply.

If the power supply contains active elements (like switching transistors and control feedback circuits) then I'm completely clueless :dontknow: Then you are getting into serious complexity.

Good luck and keep us posted!


----------

