SS amps. Why so much power?

David, no "headbanger" would ever be satisfied with a 30 wpc amp ( regardless of make, model or designer ) and 92 dB speakers. Either the amp would be smoked from overdrive or the tweeters and mids would be cooked from clipping. As to "who's gonna listen to it that loud", you might be surprised. I have locals that light power transformers on fire, blow the piss out of speakers on a regular basis, etc... Obviously, some people DO listen to music "LOUD" and i don't mean "Audiogon loud". I'm talking POUNDINGLY loud and they still want it crystal clear.

If it all boiled down to "bragging rights", you would need someone that knew what you were talking about to brag to. Since the general population all think that Bose is good and flea market car stereos have a "real" multiple thousand watt capacity, we'd be wasting our time and money.

Like anything else, people invest their time and money seeking the results that will make them happy. Since playing at high volume with good clarity and control typically takes a lot of driver surface area and power, that is what they spend their money on. I know what i want and am willing to pay for it. I'm sure that others with complex systems with high wpc ratings feel the same way.

As to why i have a lot of power, most of the speakers that i prefer to listen to are a combination of low impedances, low sensitivity and have a lot of driver surface area. In this respect, Edle is right. It does make for a tough climb up-hill but those are MY preferences and i have to deal with them. This takes a LOT of muscle to keep things under control and still not sound like something is running on the ragged edge. I also prefer to let amps coast as they typically sound less congested and more refined that way. Headroom in a system means not only the ability to easily reproduce peaks and maintain dynamic range, it means "lack of strain". This way, you can achieve "cranking" volume levels without really "cranking" the amp hard. Even if you are drawing 300 - 800 watts on long duration peaks, having 1000+ wpc on hand simply means that you're still coasting.

While this may not be nearly as critical on classical, jazz, blues, etc... due to the very high peak to average ratio, rock and metal require much higher levels of average power to sustain "concert levels" and keep it clean.

While this is not meant towards anyone in specific, until you've heard and experienced ( and especially assembled ) a system that can literally raise the roof, do it with the utmost in clarity and control and do it on a continual basis reliably, you have NO idea what you're missing or what it takes. This can't be done with a couple hundred watts per channel and average efficiency speakers. It takes MEGA watts and a lot of surface area ( drivers ) which results in low impedances which means you have to have even more power capacity. Achieving the "ultimate" becomes a vicious circle rather quickly.

That is, unless you're using very high efficiency horns and that sound suits your tastes. Even with 104 db horns, i have driven 300+ wpc amps into clipping. Impressive to anyone ? No. Trying to achieve what i personally want out of a system ? Yes. Offensive to some ? Possibly ( neighbors especially ). Not quite as offensive as talking about comparing the size of ones' "johnson" though.

All i can say is that some of you need to wake up and smell the coffee. Once you do that, you'll realize that there are different brands, types and preferences for "coffee". Even with all of the different variables involved in just that, some people like to "flavour" theirs even beyond having a custom blend. Audio is no different and there is no "right" or "wrong". Just what makes YOU happy as an individual. Sean
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Jtinn, NO amps really "like" low impedance loads. While it is true that SS amps typically deal with low impedances in a more linear fashion than tube amps do ( and high impedances vice-versa ), they ALL suffer from reduced damping factor, increased heat and thermal losses, increased distortion by-products, etc... This typically results in poorer sound quality overall. I'm sure that there are exceptions to this "rule", but they would be far and few between. Sean
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Well, i know that i can still very easily hear 15 KHz at about the same amplitude that i can hear 1 KHz ( give or take ). 17 KHz is there, but not as strong. I should probably go in for a hearing test sometime soon. I know that i had some slight irregularities in the upper mids / lower treble from ear to ear.

Other than that, i can pretty easily detect amplitude changes well under .5 dB at 1KHz, as i have to do so on a daily basis at work. I typically tune communications receivers by ear but have a Sinad meter ( signal to noise ratio ) there to confirm what my ears tell me.

In terms of hearing acuity and localization, a salesmen told me that i was the only one out of hundreds that was able to point out where a subwoofer was hidden during a Stereophile show. My brother, who is 12 years younger and standing right beside me, did not know where it was coming from and picked another section of the room. Obviously, i'm not anywhere near being deaf. Sean
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PS... I apologize for the small explosion above. It just pisses me off when "open minded" people can't see other people's point of view. Especially when it comes to something that is so obviously subjective and personal as musical preferences and system selection.

Jtinn, how do you measure "preferences" of electronic devices ? What are you basing your criteria on to say what it likes best ?

If it is simply measurable power output, you will find an impedance where an amp will peak at and then fall off both below and above that. As mentioned above though, distortion and heat dissipation ( loss of efficiency ) will climb as impedance is lowered. Obviously, most any device will have a "sweet spot" where it will perform best i.e. reasonable distortion and heat generation with good power ouput. All things being equal, a SS amp will "prefer" or work optimally into a lower impedance than a tube amp would.

This is not to say that all SS amps work optimally at low impedances though. This is evidenced by their lack of ability to "double down" as impedance is halved. While a true "voltage source" would do this, there are very few amps built anywhere close to that. Some obviously do better than others in this respect.

If an amp was a true voltage source though, it would not matter what impedance was presented to it. The power output would increase or decrease at a linear rate as impedance was halved or doubled. As such, the amp might do more power at lower impedances, but that doesn't mean that it was running optimally there. The point of optimal operation ( or what it "liked best" ) would be that of highest efficiency with the lowest distortion. Depending on the design, that could be at any specific impedance, not necessarily the lowest possible.

Besides all of the above, damping factor is lowered as the speaker impedance is dropped. This results in less control over the drivers with greater susceptability for the reflected EMF to "modulate" the power supply of the amp. This is the reason why some amps sound good at low impedances and others don't. Their "linearity" goes out the window even though power output might increase. Sean
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David, i've used two different SS amplifiers that were biased Class A, were rated for 40 wpc and 50 wpc, doubled down at 4 ohms and were from the same manufacturer that you're currently using. These powered a set of 96 db speakers in a room appr the same size ( probably slightly smaller ) as to what you mention. It was never loud enough while retaining the clarity that i was looking for when trying to throttle the system. Hence, i upgraded to a far more powerful amp from the same manufacturer and things improved quite measurably.

Having "been there, done that" many times over, i have to laugh at thinking that one could achieve "headbanging levels" with the amount of power and efficiency of speakers that you mentioned in a room of that size. That might be an excellent system for doing chamber music but it is surely NOT suited for trying to reproduce "metal" at "headbanging levels".

As to offending me, i think that your comments were offensive to everyone that currently owns, has owned or may be thinking about purchasing a high powered amplifier. Not only did you pidgeon hole all of these people from various walks of life with different philosophies into one category, you also insulted them by commenting on their "johnson-sized" mentality.

It might only be a "hobby" to you, but it is one of the passions of life to others. Either way, one should think before speaking or posting. Sean
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As some of you might have guessed, David and i have been going "round and round" via email. Since much of our conversation pertains to information that might clarify either or both of our positions, i am responding to one of his emails publicly. This will give some of you a better idea of where i'm coming from. This may help to clarify the situation and ease some tension.

David stated that his system ( 30 wpc Class A driving 92 dB speakers ) plays almost as loud as a 250 wpc Krell driving 88 dB speakers. I believe that 100% and would never argue that point. It takes a LOT of power to overcome measurably higher speaker efficiency. I just don't think that either set-up is "loud" nor would it be "clear" due to amplifier strain when cranked up. With that in mind, David and i might not have been as far apart in perspective as it seems.

As such, I think that there have been some large misconceptions as to where i'm coming from. Most people think of a 250 wpc amp as being "BIG". It's really not when you get down to it ( unless you have HIGH efficiency speakers ). In order to achieve the levels of volume with the clarity that i speak of, David thought that i would need something along the lines of a Krell 600 to do the job. I agree that this would be a good starting point. I still don't think that it would get you there due to power losses and distortion in the passive crossover network and out of band power being fed to the drivers. The beauty of active multi-amping is that it bypasses all of that AND increases amplifier efficiency and headroom at the same time.

This information is presented here STRICTLY as a point of reference to why i have said the things that i have about volume levels and clarity. You'll also understand why i said that 250 wpc is not a lot of power.

My main 2 channel system consists of six stereo amplifiers that are actively tri-amped and total 4800 watts of rms power. It consists of amplifiers built and designed by Threshold and Perreaux. Speakers consist of three different sections per side. There is a line array of e-stat tweeter panels, a set of "double stacked" e-stat panels for mids and multiple woofers for each side.

My HT system is rated at 6400 watts rms at the rated speaker impedance, all channels driven. Amplifiers are a Sunfire Signature driving the mains and a Sunfire Cinema Grand Signature driving the center, surrounds and subs. I have six 12's, four 10's and six 8's in this system, so power handling, max spl and low frequency response is not a problem.

My bedroom system is currently bi-amped and may be going to tri-amplification sometime soon. It currently consists of two identical amps ( Quad's ) rated for 100 wpc. Speakers are stand mounted two way monitors and a pair of downloaded subs.

My computer room system uses two Kinergetic Class A mono-blocks into low impedance omnidirectional speakers. Each amp is rated at 800 watts rms into those speakers. While these speakers won't "crank", they do require at least 350+ wpc to let them do what they are capable of doing.

For the record, i do have a "low powered" system. It consists of a vintage Marantz tube amp driving 104 db horns. Some of you may have seen me recently posting a question about this in the Vintage Asylum.

Unless you've ever heard a system that has nearly endless reserves of power and you can move a LOT of air rather effortlessly, you've never heard "loud and clear" before. As i've mentioned before, most of what people think of as being "loud" is actually "distortion byproducts" hurting their ears. I'll leave it at that and hope that some of you can more clearly understand my point of view. Sean