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Old 7th February 2012, 07:08 PM   #1
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Exclamation More output power at higher loads and less power at lower loads. How it is done ?

Hello

I was looking out at some amps that perform best at higher loads.

For example:

Hifimediy T1.

- It provides 100W on 8 Ohms ( 39V 5A ? ) and 50W at 4 Ohms.

I want to know what is done in order to provide more voltage and current to the speakers because it seems to foul Ohms law ?

Forgive me if it has already discused here but I tried to search the awsner here and on the web without success.


Thank You

Last edited by Virpz; 7th February 2012 at 07:09 PM. Reason: gramat
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Old 7th February 2012, 07:14 PM   #2
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It's current limited.

100W into 8 ohm = 40V and 2.5A

50W into 4 ohms = 20V and 2.5A

Last edited by Saturnus; 7th February 2012 at 07:18 PM.
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Old 7th February 2012, 10:00 PM   #3
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Never tought of that. LOL

One may call this kind of technique just "market strategy" ?


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Old 8th February 2012, 06:29 AM   #4
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I'd call it honesty. If the output chip used is current limited then an honest manufacturer will note that it has lower output into 4 ohms instead of letting the buyer assume that it can output twice as much in as into 8 ohms.

Many amps are in fact current limited without the manufacturer noting it.
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Old 8th February 2012, 03:07 PM   #5
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Good point.
I must agree with your view.

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Old 8th February 2012, 05:07 PM   #6
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Btw, in the interest off being complete. It's current limited for the package. So if you for example used it in an active speaker with a 8 ohms tweeter and a 4 ohms woofer, the total current limit would still be 5A which would be

Woofer section ... 4 ohm ... 26.67V ... 88.9W
Tweeter section ... 8 ohm ... 26.67V ... 44.5W

That'd still keep you in the 5A limit.
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Old 8th February 2012, 08:59 PM   #7
Pafi is offline Pafi  Hungary
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I don't know what do mean.

26.67V/4ohm=6.65A
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Old 8th February 2012, 09:33 PM   #8
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Quote:
Originally Posted by Pafi View Post
I don't know what do mean.

26.67V/4ohm=6.65A
Peak, yes. RMS, no. RMS is what matters in this case.
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Old 9th February 2012, 06:23 PM   #9
Pafi is offline Pafi  Hungary
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Then write it down! Never mix RMS and peak without mentioning it!

Still fuzzy.
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