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Same watts at 8 and 4 ohms?

I'm in the market for an integrated amp and trying to sort through tech specs. My understanding of the tech aspects of hi-fi gear is limited. Looking for some clarity in regard to watts-per-channel specs.

It is my understanding that wpc at 4 ohms is typically 1.5x -2x the wpc at 8 ohms.

But I'm seeing a number of respectable mid-fi integrateds with the same wpc for both 8 and 4 ohms. The NAD 388 is one and I think this is true for several of the Cambridge Audio units at a similar price point ($1500-$2000).

The NAD features make a point of saying " 4-ohm stable for use with a wide range of speakers". 

Would appreciate any insight to what these specs mean and what 4 ohm stable really means to me. My speakers are 4 ohm speakers.

Thanks,

George
n80

Showing 2 responses by tomcy6

tomcy6's avatar
tomcy6
2,636 posts
 
I think that what Ralph is saying is that doubling power into 4 ohms is only necessary if you drive the amp to its full output. 

If your amp puts out 150 watts into 8 ohms and 200 into 4 ohms, it will drive your speakers just fine if you only need 100 watts into the 4 ohm frequencies to drive them as loud as you want to listen to them.

Is that right, @atmasphere ?

Playing your speakers (and most speakers) with 100 watts into 4 ohms would be really loud.  I think any of the amps you're looking at will drive your speakers satisfactorily.  So, as Ralph said, try to listen to the amps and pick the one that sounds the best to you.


tomcy6's avatar
tomcy6
2,636 posts
 
Building amps with huge power output is one of Dan D'Agostino's top priorities.  They are all advertised as doubling down into 4 and 2ohms.

Here is what Stereophile measured in its review of the Momentum Monoblocks:

Specified as having a maximum power of 300W (24.8dBW), the Momentum comfortably exceeded that rating, clipping at 405W into 8 ohms (26.1dBW), with clipping defined as the point when the percentage of THD+noise in its output reaches 1% (fig.5). Fig.6 reveals that the amplifier clips at 640W into 4 ohms (25.05dBW), while into 2 ohms (fig.7), the amplifier puts out 1115W (24.45dBW). As with Dan D'Agostino's earlier amplifier designs for Krell, the Momentum is a powerhouse!

https://www.stereophile.com/content/dan-dagostino-momentum-monoblock-power-amplifier-measurements

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