My amplifer is only making a popping noise!

[Starlord]

Raising the switching frequency of a design which already misbehaves in the RF world is not the way to go. It's likely to cause more issues, which you may or may not pick up on.

Do yourself a big favour and find room for 10uH inductors.

The simulations indicate a -21db drop at 1.2MHz and it only gets better beyond that.  What reason do you have to believe that this will cause new issues?  At the present time, with 2.2uF inductors and 1uF caps, even though the amp is restarting on occasion, I'm not seeing any significant noise from it on my data lines, nor any noise when I probe the amplifier output itself.  I was seeing tons of noise before I put the filter there.  So it's clearly doing its job.

That said, I'll probably try both variations this time around, and see which is better. 

[Monkeh]

What reason do you have to believe that this will cause new issues?

I haven't seen your layout and I know full well that you don't know RF design principles - intentionally operating in MW is asking for trouble.

Simply trying to save you time and money. Find the few bare millimetres the recommended filter requires.

[Starlord]

Forget about the switch-on spikes.

Green is the current through the LC reaching 1.6A, with 400KHz, 2.2uH, 1uF.
Blue is the current through the LC reaching  0.8A, with 400KHz, 10uH, 0.68uF.
Red  is the current through the LC reaching 0.5A,  with 1.2MHz, 2.2uH, 1uF.

If I'm doing it right, some of these currents will be higher if the L saturates on large signals.

I don't know why the 6R load doesn't provide enough damping on the data sheet's recommended values for the stereo version, it justs gives a box labeled Filter for the mono version.

Why did you choose 6R for the load?  Did you just pick that because it was between 4 and 8?

And if I change R to 2, to emulate two 4 ohm loads in parallel, and I probe one of the inductors, is the current I'm seeing after that initial spike what I might expect to see passing through the inductor in that use case?  In other words, if it's telling me the inductor is seeing 1.9A, am I probably safe with a 2A rated inductor with a 2.3A saturation? 

[StillTrying]

Yep, the 6R was just a guess, you might be confusing me with someone who knows what they're doing. 

Here I've changed the loads to 2R, and modulated them all with a 1kHz sine to give near max power which seems to be about 32W. (Hold the 'ALT' key while over the load and click to see the Watts.)

The peak volts across the loads is +-11V.
The peak current through the loads and inductors is +-5.5A, which might be enough to saturate the inductors ,I dunno.
The Watts in the loads at the peaks are 58 Watts.

How useful this is I don't know, but by looking at the current through the load, the 400KHz, 2.2uH, 1uF version looks the noisiest.

[diyaudio]

http://www.ti.com/lit/ds/symlink/tpa3131d2.pdf

This is the schematic for my amplifier.  The amplifier was working fine with both 4 ohm and 2 ohm loads until I added the filtering on the output.  Now it works with neither. 

The filter was intended to remove frequencies above 100KHz because the speaker wires were emitting electromagnetic interference that was being picked up by another part of my circuit.  I attempted to simulate it and it looked like it would do the job even though the inductor used is a bit lower value than the 10uH ones in the datasheet.

The only change I made was to add that filter, which is comprised of L2, L3, C1, and C4.

The only thing I can think of is that these filters have a peak near the upper frequency range, and perhaps the peak with this one was too great and that is causing the overcurrent protection on the amp to kick in, but this is happening even if I turn the volume way down, which I would assume would make it work if that were the case.

Any suggestions would be appreciated. 

The only thing I can think to try would be to remove the inductors and jump across them, but I don't have a heat gun to do that sort of rework on surface mount components.  I'm going to put my scope on there and see what I see with and without a speaker attached and report back.

Class-D amplifier LC filter is an anti-aliasing filter used reject frequencies above nyquist. 100Khz ?
The filter core used is critical, a core with low permeability that allows wide band frequencies is almost always used, if that's not correct nothing will work.
       
Note as a reference see this thread. User @Eva is just a freaking master at this topic.
http://www.diyaudio.com/forums/class-d/215657-air-core-toroidal-inductor-class-d-amp-output.html