2. amps-preamps
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Watts and power

Can somebody break it down in layman's terms for me? Why is it that sometimes an amp that has a high watt rating (like, say, a lot of class D amps do) don't seem to always have the balls that much lower rated A or AB amps do? I have heard some people say, "It's not the watts, it's the power supply." Are they talking about big honkin' toroidal transformers? I know opinions vary on a speaker like, say, Magnepans - Maggies love power, right? A lot of people caution against using class D amps to drive them and then will turn around and say that a receiver like the Outlaw RR2160 (rated at 110 watts into 8 ohms) drives Maggies really well! I'm not really asking about differences between Class D, A, or AB so much as I am asking about how can you tell the POWER an amp has from the specs? 
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unfairlane's avatar
unfairlane
140 posts
 
An amplifiers watts or amps is much like a cars topspeed, just a number. It says wery little about it`s authority, it`s punch or torque.  The amp`s weight might indicate some grunt, but just that. 
Why? because it is all about how this amp are capable to deliver it`s power fast enough. And that again depends on the internal cabling, trafos included.

And while I`m on, dampinfactor calculated from output impedance is a misunderstanding, it means nuthin. But tell me the size of your secondarys..
georgehifi's avatar
georgehifi
10,312 posts
 
sfischer1

+1 you have your finger on the pulse, and know about current delivery and wattage doubling, also about bridging stereo amps.
Others here that say a $350 3000w Behringer amp solves all that are just p*****g against the wind and some just beating their own commercial drum.

Cheers George
cousinbillyl
190 posts
 
I have Acoustic Elegance 15 inch woofers. 140 Ohm impedance at Fs. Fs is 21 Hz. In the enclosure, Fs is 32 Hz. Again, 140 Ohms at 32 Hz.

The above mentioned fabulous amp. One of the most powerful available.
3000Watts @ 8 Ohms. 6000Watts @ 4 Ohms. 12,000Watts @ 2 Ohms.

Let's go the other way;
1500Watts @ 16 Ohms. 750Watts @ 32 Ohms. 375Watts @ 64 Ohms. 187.5Watts @ 128 Ohms.

Now my poor tube amps.
140Watts @ 8 Ohms. 120Watts @ 4 Ohms. ???Watts @ 2 Ohms.

The other way;
160Watts @ ....... everything above. Therefore @ 16. 32. 64. 128 etc. it just keeps on chukin'

The average 400Watt SS amp;
400 @ 8, 200 @ 16, 100 @ 32, 50 @ 64, and, are you ready? 25Watts @ 128 Ohms.

Please correct me if I made a mistake.


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clearthink
1,421 posts
 
audiozenology"someone could build a Class D amp that can put 1500 watts into 2 ohms and sell it for <$400??  The benefits of modern manufacturing and a high volume sourcing chain, not to mention a lower margin market"

And the result,  of such "modern manufacturing" is a product that sounds awful but hey it's a "lower margin market" so that is to be anticipated and expected.
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