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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
nutty
1,928 posts
 
Madrigal Audio Labratories states: The 300-series power amplifiers operate as perfect textbook cases of a "voltage source". This is to say that they will maintain whatever the appropriate voltage might be at any given moment (given the demands of the music, and within the rated voltage output of the amplifier) without any particular regard for the currenf demand of the loudspeaker.

Because of this "voltage source" characteristic, the 300- series amplifiers double their power demands every time a loudspeaker impedance is cut by half. For example, the no. 336’s continuous rated output is 350 watts per channel at 8ohms; 700 watts at 4ohm; 1400 watts per channel at 2ohms. A "continuous" test of the no.336 at maximum power requires about 50 Ampere s at 120V.
The laws of physics refuse to be cheated. Long-term, you cannot deliver more power into the speaker than you can pull from the wall.

Stereophile also reported that the ML no.33H mono’s have a 1200 watts per channel at a 1ohm rating.

N
willemj
1,036 posts
 
Geoff did not read my earlier posts carefully enough, for my other speakers are no longer the LS3/5a (lent those to my son while he is saving for a pair of Harbeth M30.1’s) but the much better Harbeth P3ESRs.
As it so happens I once attended one of Peter Walker’s blind comparisons between his three amplifier designs. Those were the days when people began to claim that tubes sounded better, and he thought they were nuts. I subjected myself to the test rig, and did indeed think that I could hear differences. Peter was pleased no end when he could show me that I had been no better than completely random. And I learned a valuable lesson. The stricture is, of course, that amplifiers have to be designed properly. If you read the Stereophile test of his valve amplifier, you can see that Peter Walker’s own valve design does indeed perform quite well under a varyring speaker load (flat within 1dB): https://www.stereophile.com/content/quad-ii-classic-monoblock-power-amplifier-measurements That is much better than many other valve amplifiers.
It is indeed a legendary design, just like his later 303 and the more powerful 405 current dumping model that still lives on in the again more powerful 606, 909, QSP and current Artera models. As Peter told me, the only practical difference is that of more power. Since at the time I was using the ELS57’s that could not handle more than my 303’s 45 watt per channel, he assured me there was no point in upgrading to the 405. A true gentleman.
kosst_amojan
2,095 posts
 
It's generally assumed by speaker designers that the amp will be a voltage source as opposed to a current source. Consequently, speakers are designed to behave flatly according to voltage. 

All that said, I'm driving a pair of Focal 936's with a muscled up First Watt F5. The nice thing about a push-pull amp is you can get a bit more head room without hard clipping. As it sits it has a potential class A envelope of about 80 watts. But, at 8 ohm that envelope drops to 52. My Focals have a low point of 2.8 ohm. That means the class A envelope collapses to a whopping 18 watts. Sure, it will drive more power up into class AB, especially since I deleted the current limiting transistors. It's pretty easy to tell if you're pushing a class A amp out of it's envelope because they get quite a bit hotter. I've been listening to Tool's 10,000 Days here loud enough to feel it in my chair for a cool half an hour at least. The amps is still at idle temperature. It's probably not belting out 18 watts much, if at all. And if it does at that impedance low point it just transitions to class AB. 

This thing is about all the amp I need and these aren't the easiest speakers in the world to drive. I have no idea why people need 500 watt amps in a normal sized room with decently sensitive speakers. I'm not sure why people get so worked up about an amp's ability to double it's current into half the load. 6moons reviewed the F5 and noted that if your speakers need more that the F5's 25 watts they're probably poorly designed and I tend to agree with that based on what I'm hearing right now. I seriously think people should listen to a simple, well designed, low power amp before they form opinions about the importance of current delivery ability and kilowatts of power potential. It sounds like @ghosthouse  discovered that. I think Fist Watt amps represent exceptional, perhaps unmatched, value in terms of quality for the dollar, and I doubt much of anybody really needs more power. 
willemj
1,036 posts
 
An interesting way to look at the issue is to measure a so called power cube. The late Peter Aczel had the instrument to do that, and here is an example: http://www.biline.ca/audio_critic/audio_critic_web2.htm#pa
willemj
1,036 posts
 
Too late to edit my post, but see here: http://audiograph.se/
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