Watts! How many do we need?

Current and output impedance are important as well. Paul from PS Audio gives a good explanation here.

@dogearedaudio 

My point was that I have seen systems so expensive, so complicated and striving for so much power and scale that they become unmanageable for the owner.  They're often difficult to listen to as well.

Point taken. But in this context we are talking about modern power amps/integrated amps that put out high-current, 300 wpc plus into a pair of small to medium size speakers. And in the case of Harbeth's, were designed/voiced for SS. 

Conversely, I'm hoping to put together a much lower powered tube system again when circumstances allow it, but maybe with some vintage Tannoy's or similar. (I owned a 35wpc Raven Audio Osprey that was oh so sweet sounding - I miss it)

No question both high-power and low-power strategies can sound fantastic when the synergy is right. 

Sanders has a vast knowledge I have some of his amps and speakers they are great.  As stated power is volts x amps.its the transients that take alot of watts.its the clipping that causes damage to speakers.it is well known esl take alot of power but big cone speakers do also. Some speakers are efficient that's why the reference 1 watt produces spl sound pressure level. As a standard to compare. There has to be some relationship to reference to be marketable.i have read some high powered amps don't play well at low volume but I have not experienced it. The class d amps are getting better and have alot of watts for lower price.they are put in many speakers these days.i like big speakers because I have the room.the huge watts bring them alive.i have alot of esl and planars from many decades.alot of speakers are putting ribbons in now.some of them have 32 ribbons each and require lots of power.paul mcgowen put a 1k watts each speaker into each of his irs v woffer tower they have 6 each colum.enjoy what you have and the music.stay healthy

@bigtwin Your explanation was super helpful, thank you! It's why it's worth coming here....

Your speakers are not as hard to drive as sensitivity of 85-86 db. You don’t deep under 5-6 ohms. Big speakers like Wilson’s that are dipping into the 1.6-1.5 ohm range need a way more powerful amp even if they have a 91db sensitivity.

Digital metering with a peak hold function is more accurate than physical meters.

P=I squared R or V squared/R It is hard to get away from the fact that current and power are extremely closely related. You know an amp has an adequate power supply if it doubles down to 2 ohms. 

There is no such thing as too much power. How much power is adequate depends on the speaker and listening habits of the individual. Since every 3 dB doubles the power requirement power requirements increase dramatically with volume. To get bass at realistic levels and depth always requires a lot of power especially if room correction is utilized, in the thousands of watts. 

From my experience with solid state, current was the primary determinant if the amp was up to the task, the more the better. From my tube amp experience, it is far, far less important. So I went from high current 350 wpc solid state to 70 wpc tube amplification and my system sounds so much better it is amazing. It is a high quality amp… I am sure there is a difference between 70 wpc with an inexpensive light weight tube amp and a good one.

@ghdprentice 'Current' in the way you describe it above has little or no meaning. You might want to read this article which explains why.

@jfrmusic If you need over 100 Watts to make your speaker really sing, you have a problem- the speaker might be criminally inefficient unless you are in a very large room. The more power you need, quite often the harder it is for the amplifier to sound like real music. Most higher powered amps I've seen simply don't, although they are pretty good at sounding like electronics.

I need 1 to 2.  My amp puts out up to 4.5.   Lots of headroom.

Jerry

Hi @atmasphere,

Thanks for your comment, but I am pretty sure I understand current and how it relates to solid state amplifiers performance characteristics. Sorry, but the article you refer to is so poorly written as to escape making any sense to me, hats off to you if you can understand the techno babble, with a bit of some kind of marketing. I am familiar with ohms law.

In the 70’s the power measures of peak watts and then RMS watts were shown to be grossly inadequate. This is when current came into the discussion. This is also when the first high current designed amplifiers were created. The first was the Threshold s series. I purchased the s500 after amp after amp failed to adequately power my speakers. The s500 would produce over 2.5 amps into 8 ohms and much more into lesser resistance. My next amp was a Pass x350 which would develop over 5.5 amps. This I found very amazing as I used an arc welder that produced 6 amps on constructing steel prototypes for work in the mid seventies. Anyway, through these and other high current amps I have used over the decades showed it to be a very positive guide to the solidity and resilience of solid state amplifiers.

I have a bunch, and I’m thinking I use almost all of them. 1000 each in my Legacy IV 2 Amplifier. It runs the Legacy Focus SE’s Mains. 600 each in my 5 channel Legacy IV 5. It runs my Side Phantom’s and Rear Deco's plus the Center Marquis. All are Legacy. Not sure about the 4 subs I have. They are Legacy Foundations and have 1000 each. I invite folks over and we play video Concerts. I try to keep the system humming at 113-115 DB with my Tripplet meter. It’s better than a true live concert. The punch is unbelievable. Favorite is the Eagle’s Farewell tour. Just killer. We are 10 feet back from the soundstage. 65-inch Sony Q-Led does the video. System never heats up, and we always play the entire two-hour concerts. Can lay your hand on the Amps and they are barely warm. Sometimes we pause as I get questions about the system and its impossible to talk. But I USE my system.

He more the better.

there is an openness, a feeling like sleeping in birthday suit,

an ease to the sound, smooth, no clipping, no mumbled distorted passages, 

the amps don’t work too hard, they will,sail along n cruise control doing what they do best.

I’ve had small amps, med, large, and,now I’ve learned,when you want to my e air with ease, you need the,power.  
 

sure a 6 w with 991w1m will work, but when you want to rock, you,can’t. 
 

Anyone that listen at 113-115db are either def or stupid, or if doing it routinely maybe both?

If you are not def, is it then something you aspirer to be ?

Why would a music lover try to intentionally destroy one’s hearing?

As older we get our hearing for most people deteriorate and unfortunately for many it hinders their ability to function 100% in social gatherings and for some people they choose to redraw a bit from social life.

Also as it is now, there is nothing you can do if getting tinnitus which even is a much bigger problem.

i worry about the younger generation that blast music into their ear canal’s with in-ear headphones, I am guessing that most of them will have big hearing/tinnitus problems before they are 50!

Thanks for your comment, but I am pretty sure I understand current and how it relates to solid state amplifiers performance characteristics. Sorry, but the article you refer to is so poorly written as to escape making any sense to me, hats off to you if you can understand the techno babble, with a bit of some kind of marketing. I am familiar with ohms law.

@ghdprentice I'm going with 'apparently not' in this case. The reason, which is pointed out in that article, is that current does not exist without Voltage and the two together make power according to this formula, which is quite simple:

1 Amp times 1 Volt = 1 Watt.

This means that if the amp can make the power, it has the current also. So it makes no difference if the amp is tube, solid state or class D.

When there is talk about current, absent of power, then its nonsense. For example, quite often solid state amps are advertised as having lots of current; not picking on anyone in the industry but I've seen '80 Amps' advertised many times.

Since Power is also (through algebra) equal to Resistance times Amperage squared, let's give the 80 Amps the benefit of the doubt and set Resistance to 1 Ohm. Thus the power is the Amperage squared. In the case of 80 Amps, that's 6400 Watts. To my knowledge there are no amps offered to high end audio that make that kind of power: Amps that make current beyond the power they also make do not exist.

If you think otherwise you are engaging in a myth. That is why I linked the article.

I like the simplicity and purity of the SET. But I also prefer inefficient planar magnetic speakers (Magnepan 0.7 which is all quasi-ribbon because pure ribbons are too fragile). I let a globe 45 SET transformer couple to an 833A run at 1000 Volts and Hammond output transformers. This does not push it to high wattage, but easily drives such speakers well below audible distortion and is as loud as any concert hall.  

@atmasphere  , is it watts that drive the speaker?  (I know that if I put the + & - lead of my vm on the corresponding speaker posts. I get an AC volt reading which varies depending upon volume level.)  But if it is watts that drive the speaker, and every watt is equal to every other watt, what is it that makes speakers sound different with different amps?

Two Futtermans at 135 watts each.

Altecs are 101 db efficiency, 16 ohms.

The can play twice as loud as I could ever tolerate.

see

theaudioatticvinylsundays.com

@atmasphere  There is actually a high end audio amp that can make 6,000 watts RMS into 2ohms the Dan D'Agostino relentless 1600. 

is it watts that drive the speaker? (I know that if I put the + & - lead of my vm on the corresponding speaker posts. I get an AC volt reading which varies depending upon volume level.) But if it is watts that drive the speaker, and every watt is equal to every other watt, what is it that makes speakers sound different with different amps?

@immatthewj Watts drive the speaker. But most speakers are designed to be ’Voltage driven’. "Voltage driven’ is a short hand phrase that basically says the amp, while making power, should be able to act as a Voltage source, which in turn means that the amp can make the same Voltage regardless of load. You are familiar with what this looks like already: if the amp can double power as the speaker load impedance is halved, then its a Voltage source.

So the short hand can be confusing. However Voltage does not exist without current being present and vice versa. So in the end Watts are actually driving the speaker.

The reason amps sound different is how they make distortion on a particular speaker. Our ears convert distortion (harmonics) into tonality in the same way that harmonics of musical instruments define the tonality of those instruments. The ear is particularly sensitive to higher ordered harmonics (the 5th and above) since it uses them to tell how loud a sound actually is. But those harmonics can be masked from causing tonality if the 2nd and/or 3rd harmonic is high enough- this is why SETs seem to sound so musical despite having a lot more distortion (including higher orders) than any other kind of amp; the 2nd and 3rd harmonics are masking the higher orders.

Solid state amps often have much lower amounts of distortion overall, but the higher orders are not masked, causing the amp to sound brighter and harsher.

The most musical amplifiers are those that make very low amounts of distortion (SETs are typically 10% at clipping so they are right out) and that distortion will be the 2nd and /or 3rd harmonic, enough to mask any higher orders.

@invalid Yes, that’s true. But they advertise that pesky current thing on their website- take a look (and click on 'specifications').

Now lets do the math:

Giving the amp the benefit of the doubt, we set the speaker load impedance to one Ohm. Using the Power formula thus the Power the amp makes is the current squared. This amp does not make 160,000 Watts! They claim 6000 Watts into 2 Ohms, so the current flowing at that time is only 54.77 Amps... and if it doubles power into 1 Ohm (which it probably can do but not to full power) it would be double the current or only 109.54 Amps.

Obviously that current spec is something entirely different!! Most likely its 400Amps that flows when the power supply is shorted out for 10mS. So its really a measure of the capacitance in the power supply rather than the current that the output section can produce.