2. amps-preamps
  3. 159074-115924

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
invalid
1,190 posts
 
I doubt any amp can really double it's power with halved impedance. Most of the amps that say they do are actually underrated at the 8ohm impedance.
georgehifi's avatar
georgehifi
10,312 posts
 
I doubt any amp can really double it’s power with halved impedance.
If you take literary then no, it would like perpetual motion then "impossible"

"Almost" double, it’s wattage is the operative word, 8 to 4ohms, 4 to 2ohms and in the ML2’s case 2 to 1ohm

Cheers George
invalid
1,190 posts
 
I would still think the ML2 would be more than 25 watts into 8ohms. My vintage krell amp is 300 watts and is supposed to double, but it measured higher than 300 into 8ohm, so the manufacturer did underrate the amp to get to that doubling into 2ohm and under.
georgehifi's avatar
georgehifi
10,312 posts
 
I would still think the ML2 would be more than 25 watts into 8ohms
They are, when keeping respectable 8ohm distortion figures, losses, as they only have 20v or 25v rails for memory.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
Story time!!

Absolute Sound:
One of the Ten Most Significant Amplifiers of All Time

Stereophiles John Atkinson: HQD LOUDSPEAKER SYSTEM and ML2’s
I first heard the Mark Levinson HQD loudspeaker system some ten years ago, at the Festival du Son in Paris, in the days when it was a real hi-fi show. Perhaps even more so than by the speakers, however, impressive as they were with their stacked Quads, Decca ribbon tweeters and Hartley 24" woofers, all in beautiful beech woodwork, I was bowled over the amplification used: six Mark Levinson ML-2 monoblock power amplifiers. Capable of just 25W output each, these class-A monsters were the first true high-end amplifiers I had ever heard. The memory of effortless low-frequency reproduction, coupled with a magically liquid midrange, lingered on.
The ML2’s drove these double stacked Quad 57’s with Decca Kelly horn loaded ribbon tweeters from 10khz up, and used 2 x 24" Hartley bass units from I think it was 80hz down.
http://www.kaponk.com/2019/08/15/hqd-loudspeaker-system/

A friend Otto Major (rip) Quad 57 restorer guru. had this very speaker system, except the amp used was my own built 150w Class-A water cooled self contained mammoth of an amp, 2 preferable 3 man lift.
This system, it was something to hear. The Harley’s were mounted in the brick wall behind the Quads and they used the next room!!! as the speaker box. the FS was I think 16hz.

Linn LP12 Black Widow arm with the best cartridge I’ve ever heard a Stax CP-X Electrostatic cartridge.
https://www.vinylengine.com/turntable_forum/gallery/image/11682/source?sid=eefee7d56ce857f513c305e4e...
https://www.vinylengine.com/turntable_forum/gallery/image/11675/medium
That used a tube HT power supply. Here one dismantled for repair.
https://www.vinylengine.com/turntable_forum/gallery/image/15730/medium

https://www.vinylengine.com/turntable_forum/gallery/image/11679


Cheers George







More to discover