What happens to an amp below 2 ohms?

The lower the impedance, the more current the speaker tries to draw from the amp.

With transistor amps, this will certainly result in more heat as the current has to come through the output transistors, even if the amp is class D. Some SS amps have enough current rating in their output sections to support this and others do not.

Tube amps will not produce any more current at all- usually they will put out less power as a result, although with a set of ZEROs http://www.zeroimpedance.com installed, they may be just fine.

Now for the *effects* of a low impedance like that (IOW: the bad news). No matter what kind of amplifier you have, if sound quality is your goal, it will be at a disadvantage driving a load like this, even if the amp has the current to do it. OTOH if *sound pressure* is valued over sound quality, then this *might* be OK, but if that is the case you are often better off seeking a speaker that is higher efficiency that might be a little easier on the amp.

The reason SS amps don't sound their best into lower impedances has to do with internal capacitances that exist in the junctions of the output devices. In most cases, this capacitive element is non-linear. It is magnified by increasing the current through the device- precisely what happens when you use a lower impedance load. This results in greater odd-ordered harmonic distortion, making the amp sound harsher and less transparent.

If you prefer a smoother, more transparent sound then you will find this a good argument to seek a speaker that has a higher impedance.

Isn't sound quality everyone's goal?

Surprisingly, no. Many audiophile revel in that fact that they can weld with their amp, or drive loads like that, even though there is no sonic benefit whatsoever in doing so.

Are you saying that people who have electrostatic or ribbon or planar speakers where the load impedance dips below 2 Ohms are not enjoying quality sound & that they are merely reveling in high SPL music environments in their respective homes?????

No, what I am saying is that if those 'electrostatic or ribbon or planar speakers' were higher impedance the owners would be enjoying even better quality sound.

We can look at this from a very basic point of view. If a speaker has a reputation of being 'difficult to drive' due to low impedance, the reason that phrase is used has to do with the fact that the amplifier has a difficult task. Don't think for a minute that there is no price paid for that! The amp simply will not sound as good.

In addition, speaker cables get **critical!** when you are driving lower impedances. With higher impedances the cables are far less critical and can be run longer distances.

Rleff, its a matter of power- in some rooms you have enough power with MA-1s on the big Sound Labs and in some rooms you simply need more. But you would not need ZEROs in any event.

Bombaywalla, the word was 'phrase', not 'phase'...