Which watts are the right watts in SS amps?


Hello Sports Fans!

More than a few people over the years on these pages have said only those SS amps which double down in output power as impedance drops are truly special or worthy amps. Eg., 200 @ 8ohms; 400 @ 4 ohms; 800 @ 2 ohms; etc.

Not every SS amp made does this trick. Some very expensive ones don’t quite get to twice their 8 ohm rated power when impedance halves to four ohms. BAT, darTZeel, Wells, and Ypsalon to name just a few.

An amps ‘‘soul’’ or it’s ‘voice’ is the main reason why I would opt in on choosing an amp initially and keeping it. Simultaneously , I’d consider its power and the demands of what ever speakers may be intended to be run with it or them.

I’ve heard, 80% of the music we are listening to is made in the first 20wpc! I’m sure there’s some wisdom in there somewhere as many SS amps running AB, are biased to class A Only for a small portion of the total output EX. 10 – 60 wpc of 150 or 250 wpc.

After all, any amps true output levels are a complete mystery when anyone is listening to music anyhow.

I suspect, not being able to actually measure true power consumption, the vast majority of listening sessions revolve around 60wpc or so being at hand with traditional modern reasonably efficient speakers.

Sure, there are those speakers which don’t fit into the traditional loudspeaker power needs mold such as panels or electrostats, and this ain’t about them.

The possibility of clipping a driver is about the only facet in amp to speaker matching which gives a person pause while pondering this or that amplifier.

I feel there is more to how good an amp is than its ability tou double output power with 50% drops in speaker impedance.

However, speakers are demanding more power lately. Many are coming out of the gates with 4 ohm ‘nominal’ IMPs which lower with fluctuations in frequency. Add in larger motors on larger drivers, multiple driver arrays, and on paper these SOTA speakers appear to need more power.

IMHO It is this note which introduces great concern.

I’ve read every article I can find on Vienna Acoustics Music. Each one says give them lots of watts for them to excel.

Many times good sounding speakers I’ve owned sounded better with more power, albeit from arguably a better amp.

I tend to believe having more than an adequate amount of cap power is indeed integral. … naturally the size and type of transformers in play possess a strong vote for an amps ability to successfully mate with speakers.

Controlling a driver’s ability to stop and restart is as well a key to great sound and only strong amplifiers can manage this feat. Usually this gets attributed to ‘damping’ factor, but damping as I read it is more a shadow than a tangible real world figure as it depends on numerous factors. Speaker cable length alone can alter damping factors.

A very good argument exists about those mega watt amps voices. Each 500 or 600 wpc amp or amps, I’ve heard have had stellar voices too, not merely more watts.

So is it predominately these mega watt power house amps souls or their capacities that fuels the speakers presentation?

Would you buy an ‘uber expensive’ amp based more on its voice or soul, than on its ability to output loads of watts, even if you feel the amp may be somewhat under powered for the application?

Choosing this latter option also saves one money as the more powerful amps do cost more than their lower outputting siblings.

Please, share your experiences if possible.

Tanks muchly!

blindjim
It's useless to talk about 4ohm speaker and 8ohm speaker, as none are flat at that impedance across the audio band, they are very different. And the best way to treat it is to look at the lowest impedance and - phase angle and base an amp around that.

1: There can be dips in the impedance curve at certain frequencies that can be very low. 
2:There are also negative phase angles at certain frequencies that can be very high.

Combine the one and two at certain frequencies and you have almost a short as seen by the amplifier "usually" in the bass.

EG:
Wilson Alexia is spec'ed by Wilson at 90db and 4ohm

Independent test measured:
I in the power region of the bass between 60hz and 110hz approx it has a nominal impedance of just 1.9ohms!, combine this with the negative phase angle of around -45 degrees and you have an EPDR (equivalent peak dissipation resistance) that the amp sees as just .9ohm!!!!!   

So much for being designated as a "4ohm speaker"!!!
And the Sofia 3 is even worse than this.

Cheers George


   
  
The conclusion is that good engineering demands speakers that are easy to drive and amplifiers that retain a flat frequency response under varying loads. Combine such units, and you are fine. Combine hard to drive speakers with most tube amps and you have a response that is all over the place.
good engineering demands speakers that are easy to drive

This would be great, maybe in the future with different construction techniques, motor design, materials ect, but for now easy to drive speakers usually have other permanent compromises, that can’t be fixed driven by the right amp.
At least the expensive hard to drive speakers are just that because they present no compromises except one, being asked to be driven with amps that can drive them with the current that's needed. 

Cheers George
Got it.

Thanks Al.
= = = = = =
More than interesting.
Thanks George.

Do you know if the Sabrinas and later model Sash’s have similar IMP traces as the Wilson’s you just mentioned here?

I’m hearing from this person and that, they have listend to the Sabrina and Sasha with very modest power amps, even < 100 wpc., tube amps and really enjoyed what they heard.

BTW, Does that third party measuring facility come with any verifiable credentials? What’s the annual subscription run? Do they cover as much as Stereophile, or more?


Again, I do appreciate the input and all the effort.

Combine hard to drive speakers with most tube amps and you have a response that is all over the place.
Yeah EQ'd to the sh**-***se, some call this tube sound or euphonic's. I call it an equaliser.

Cheers George