D-Sonic peak current output compared to other

Let's do the math!

We have three values mentioned so far. 30A, 45A and 65Amps.

Exactly what does that mean? I suspect it is not having anything to do with the power output of the amp. Let's see if I am correct.

The power formula is P=Isquared x R. P is Power, I is current and R is the load of the speaker.

Let's assume that the speaker is one ohm, which it isn't in most cases, but one ohm means that the power is equal to the current squared; 30 amps is thus 900 watts, 45 is 2025 and 65 is 4225.

If the speaker is 4 ohms the power level becomes 2700 watts, 8100 and 16,900 watts respectively.

Do any of these amps make power like that into 4 ohms? No? (sorry to be a bit flippant, but this is an often misunderstood spec).

The actual spec is the amount of current measured when the power supply is shorted out for 10 milliseconds.

By that measure, our MA-2, a 220-watt tube amp, has as much current as the most powerful amp mentioned on the is list so far. But its really the amount of *power* that the amp can make into the speaker load that is important.

The current spec is really a measure of the size of the pool of electrons that feeds the amp. But the amp is a bottleneck for that pool. It has been shown that amps with more power supply reserve do sound better- this is often simply because you get less IM distortion.

One other bit of math. Let's say the speaker is being fed 400 watts. What is the current? If a 4-ohm speaker, the current is 400=Isquared x 4. Solving for current we get 100, taking the square root we get 10. Ten amps is all that is needed to drive a 4 ohm speaker with 400 watts. Note: it does not matter what kind of amp is used, if its 4 ohms and 400 watts the current will always be 10 amps.

Amplifier manufacturers like to use that current figure to inflate the idea that their amp is more 'brutal' or something, I hope this rather simple math allows you to see what is really going on.

Not sure I buy the explanation in the video. It needs elaboration to know what he is trying to say.

There are a number of things in the excerpt above that are patently false (despite the source) but are indeed widely-held opinion in the form of myth.

For example the ability to play deep effortless bass has nothing at all to do with the ability of the amplifier to double its power as impedance is halved.

If you would like an example of this, try that of a Sound Lab ESL being driven by a transistor amplifier. The tendency is for the amp to be bass-shy on that speaker while also being too bright.

What in fact is far more important is the relationship between the amp and speaker, as well as the intention of the designer of the speaker. Very closely related to this fact is the experience of seeing 'good' specs on paper, but also knowing full well that the specs will not tell you how that amp will sound in your system.

Here is an easy to read article about what is going on:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

Most box speakers have a woofer in that box that makes the bass. The woofer has a resonance in that box that is expressed by a peak in the impedance curve. This usually shows up in most designs right near the low frequency cutoff of the speaker itself. So you can see that the comment:

amplifiers that can continue increasing their output power as the impedance drops generally have very deep, extended, and powerful bass

is not really true at all. In fact making deep bass has nothing to do with 'tons of current', since at the resonant peak in the box, the speaker's impedance will be high, not low, forcing the amp to make *less* power, not more! Obviously something else is at play in the way amps make good bass.

It is true that lots of capacity in the power supply (which is the source of the 'amplifier' current that generated this thread) is generally associated with the better amplifiers made. But it is the relationship between the amp and the speaker that actually governs the things we hear from them. Understanding that fact is how you avoid flushing large amounts of dollars down the loo.

At the end is the music that matters. Your amps sound great, so do Parasound amps and many other amps out there with totally different designs.

Isanchez, this quote above really says it all- and also points to the fact that current is in fact not what does it.

Here is why:

Power (watts) is created by amps and voltage. The formula is P =I x E, where P is watts, I is current and E is voltage.

What this formula tells us is that if there is no voltage, there is also no power. We can apply this in a practical fashion; if we have an 8 ohm speaker driven by 100 watts the current is going to be a function of the voltage divided by the resistance of the load (8 ohms). So if we plug in the numbers, we see that in this case the current is about 3.54 amps.

However without the voltage the current is zero. So it is indeed power (watts) that is doing the work, not current (another way of putting this is it is impossible for current to flow without voltage). What is happening here is that there is a convention, the Voltage Paradigm, which is in play. It uses commonly-used electronic terms, but in ways that are not normally used outside of the audio industry. The term 'output impedance' is an excellent example, and another one that relates more directly is the idea that speakers are 'voltage driven' when in fact such is impossible without current. This leads to all kinds of confusion when people who think they know something about electronics see these terms used but don't realize that they have a different meaning. Do you see what I mean?

The quote from Robert Harley is his opinion, but is incorrect as the math does not agree with him. But we are talking about a very commonly-held myth, and such things don't die easily, even when faced with that math! Mind you, Ohm's law and the power formula are inviolable, which is to say unlike a speed limit they can't be broken. They are basic laws of physics.

Simon, Are you saying that your amplifier can produce peaks of 65Amps? Or are you saying that when shorted, your power supply can produce a peak of 65Amps for half a second?

Both are impressive specs, however the former is not credible. It suggests that your amps can make a peak power of over 4000 watts into one ohm, and over 16,000 watts if a 4 ohm speaker. So I am assuming you mean the latter?

Simon, I noted the last comment in that article. You might be interested to know that there have been studies of how the brain reacts to music- and where that music is processed.

The studies were conducted by Dr. Herbert Melcher, a neuro-chemical scientist.

What his studies show is that there is a tipping point that occurs in the subconscious brain. Normally music is processed in the limbic portions of the brain (which is the source of emotional reaction). Unlike the conscious portions of the brain, the subconscious parts are not fooled by poor audio reproduction. There is a tipping point wherein if too many of the human hearing perceptual rules are violated, the processing moves from the limbic centers to the cerebral cortex (seat of the conscious brain).

I thought that you might find it interesting that he has some pretty hard numbers on this subjective experience :)

I see this as the tip of the iceberg. The more we know about how the ear/brain system perceives sound, the better we can make audio systems for musical reproduction. It seems pretty obvious that we want the limbic centers to do the work :)

Simon, I think we are on the same page- IMO, distortion is pretty much the name of the game!

It turns out that the ear hears distortion as tonality. This is why SETs sound so lush, because of that 2nd harmonic. Its been my experience that if the system is working right, you can play it at high volume without really being aware of how loud it is, because there are no artificial loudness cues (which are higher ordered harmonics like the 5th 7th and 9th). IOW, if the system ever sounds loud, something is wrong.

The more you get rid of distortion, the smoother, more relaxed the presentation is, along with increased detail, as the presence of distortion masks detail.