Interesting UPA-5 question

[bignorm]

Hello..

I was hanging out over at the AVS forum and a question has been asked about the UPA-5 600va transformer ...the question being "how can a 600va transformer output 125 watts continuous power into 5 cahnnels"

just wondering your thoughts on this

[bobydee]

I think people are still confused as to that question, as seen in this thread:

emotivalounge.proboards.com/index.cgi?board=amps&action=display&thread=12891

[DYohn]

Aug 6, 2010 21:06:55 GMT -5 Lonnie said:

We use the Adio Precision to run all power test which meet all the requirements of the FTC spec.

All power specs are rated across the entire frequency band, at the specified THD level, with all channels driven.

So the pwer we state is the FTC rating.

[michaeljhuman]

I would be curious as to how you can generate Y watts of output power with X watts of input power when X < Y. Transformers can be driven beyond their rating I believe. And the FTC rule as I understand it calls for 5 mins of continuous power. So maybe that helps answer the question.

But I would welcome a more comprehensive explanation of the situation.

[michaeljhuman]

I read through the thread posted above. Lots of people posted without directly addressing the issue. Or at least what I think the direct issue is. To the best of my knowledge, and I could be wrong, FTC specifies what continuous means.

I had thought it was 5 mins based on some info I found online. It may have changed, or my info may have been wrong.

It seems that the posted data from Audio Precision was for a test run much shorter than 5 mins. Emotiva claims they follow FTC rules. Not having seen a current copy of the rules, I can't address that. Maybe they do.

I do believe the amps can hit the power figures shown at least for a short time. Given that peak demands are for a short time, perhaps that's good enough. In other words, you won't want for power. In fact, I suspect that people's power needs are likely less than they expect - not everyone's, but many people's.

I believe that's all I can add to the discussion I did ask for a clarification of FTC continuous power in that thread, but I don't expect to get a definitive answer.

[NorthStar]

Well, don't forget that this 600 VA transformer is a High Current Toroidal one.

- Also, it has 90,000 uF secondary capacitance.
- Also, each separate amp has 4 output devices per channel (as opposed to only two in most receivers).
- Also, the rating is into 8 Ohm loads with 125 watts times 5 with 0.1% THD. (Important spec)
- Also, it uses a Triple Darlington with On output stages.
- And it weights a very healthy 58 pounds (net).

* The circuit design, the implementation of all the parts contribute to its overall power and performance.

** Some amp's designs also rely on the A/C current from your wall outlet.
...For example look at some designs from Carver (Bob) and its tremendous power (400 watts+ per channel) and some of his amps weight less than 40 pounds!

*** The size of the Main transformer is only one aspect of a mutichannel power amp.
It does not tell the entire story alone by itself.

Capitch?

-> The true end result is not in the lab tests, its in real world application with real software from Movies and Music.
And that I truly believe that the Emotiva UPA-5 mutichannel power amplifier does that in full spades, flying colors.
And at the price, it's a Full House! Or even a Straight Flush, a winning hand...
I even heard that 007 (James) strictly use Emotiva amps in his own system!
And no wonder his last name is Bond, as he perfectly bonds with those amps!

Now if you don't believe me, just ask him!
...He's actually online right now (at the Lounge) as he prepares for his new Bond film: "La Carte Blanche".

[michaeljhuman]

Most of those things you mention don't help with the basic problem which is that the power transformer needs to provide at least as much input power as the amp produces output power, for continuous operation (as mentioned above, it was not clear how long continuous is with regards to the FTC amplifier rule.)

Filter capacitance can provide additional short term power, I agree. As mentioned above, I had thought the FTC amp rule called for 5 mins of operation. I am pretty sure the caps would be drained in a much shorter time than that.

A Darlington output circuit ensures the transistors operate in their safe operating area. It does not change anything in terms of how big of a transformer is needed.

As for the transformer being high current, I would not know about that. They are usually rated in terms of VA not current.