What Class D amps will drive a 2 ohm load

Just asking.

I see specs into 4 ohms but nothing into difficult speaker loads (like Thiel CS5's).

Thanks for listening, 



You guys have me thinking. I’m not at all on your level of knowledge.
So now is a good time for me to throw this out there. I have Legacy Focus mains, with Legacy Marquis center and a nice pair of Ascend Acoustics Sierra 2 raal surrounds. Couple of 18 inch subs also. We do up some video concerts while entertaining, classic rock mainly, and volumes stray up over 110 db ( at 10 feet ). The sound in that room is phenomenal. I had a new ATI Signature 6005 series amp, and occasionally the right channel would just quit. I called ATI. They were really nice about it and explained that probably the Legacy’s were dropping below 2 ohms and tripping the channel. ATI then called Legacy and found out that they indeed did go down to 3 during certain conditions. ATI replaced the board with one that could take more punishment, no questions ask. Here’s my question. Legacy has just released their "V" series amps. They are D series with Ice technology. It's double the output of my ATI. 600 verses 300 per channel . It sounds like a perfect fit to me. Any drawbacks ? Please don’t scold me on the effects of loud listening. I’m 64, been racing cars and enjoying loud hobbies my entire life. Too late to cradle myself now .. Thanks for any input.

I have Legacy Focus mains

Very nice speakers but sorry a b***h to drive, neither your amp (mosfet) or a class-D will suffice, they’re just not up to getting the very best out of these Legacy’s

That’s a pretty nasty looking impedance and -phase angle graph.
Read back at amps I have suggested and you get the idea of what you need.
Doesn’t have to be high wattage 50-100w will do, as those speakers are 95db, BUT!! you need gobs of current all the way down to 2ohms, look at what I say about "almost doubling wattage" for each halving of impedance, then go and search for amps that come close to doing this.

(fig.1) reveals that it needs to be used with an amplifier that can deliver high current into low impedances.
Not only are there two minima in the bass of less than 2 ohms, and another of less than 3 ohms in the mid-treble, but there is an amplifier-crushing combination of 3.3 ohms magnitude and 60 degrees capacitive phase angle at 20Hz

Cheers George

@nitrobob - it would appear that V series amp is based on the IcePower 1200AS1/2 modules (not sure if it’s the 1, 2, or combination of both), which has a minimum impedance of 2.7 ohms. They also mention you should use a 20amp circuit for best results.

You might want to consider using a high current stereo amplifier for left and right channels only, and something different for the center, and surrounds.
Thanks guys. My current ATI 6005 uses two 20 amp circuits as I had to run a dedicated line for my second output.
OK, so what is the definition of instability for these Class-D amplifiers?
Stability is the same definition regardless of the kind of amplifier. It is the ability of the amplifier to resist oscillation.
Oscillation has nothing to do with whether an amplifier can double power as impedance is halved, and has nothing to do with whether or any such nonsense. Its simply means the amplifier won't oscillate.

Now one thing that potentially could muddy the waters: it is possible to build a class D amplifier that is self-oscillating. This is done using the feedback loop with the intention of using the oscillation frequency in the encoding process of the amplifier. This is a handy technique as it also allows the amplifier to correct for phase shift in the audio passband. But such an amplifier could still be able to oscillate independently of its self-oscillation if there were a design bug! Confusing- but there it is.