The entire backside of the heat sink is occupied by 64 MOSFETs, 16 for each of the four transformers. Normally, I'd call these devices "switchers" to drive the transformers and create the positive and negative rails, but this is where we deviate substantially from every other amp. These MOSFETs do actually drive the transformers, but not at a steady rate to create a "reservoir" of output power. They actually drive the transformers directly to the speaker outputs in a pulse-width modulation fashion. This effectively eliminates the section of the amp that would normally be called the "output" section, and also eliminates the efficiency losses associated with output sections, whatever class they may be.
Let's look at the input section. The analog music signal from your head unit enters the amp by way of a pair of gold-plated RCA connectors, and goes pretty much straight to a Texas Instruments DSP chip. There's plenty of support circuitry around the DSP. In fact, the input board is about 6 inches by 8 inches, but all of the processing goes on inside the chip. The gain, crossover, bass boost, and limiter controls are all single element potentiometers that feed reference signals to the DSP chip. In other words, they have no direct effect on the analog signal; they just tell the processor what you want it to do. Once the analog signal enters the DSP, there's no more analog signal until you get to the output filter at the speaker outputs. Because the crossovers and bass boost are handled in the digital domain, the curves are picture perfect and very precise.
Here's where things get even stranger. In a typical amp you have an input stage, a power supply stage, and an output stage where the first two stages work together to kick out the tunes. The power supply runs at a constant rate, creating a "reservoir" of power (called "rails") that's fed to the speakers through the output transistors as the input section commands. In the Warhorse, there's an input stage as usual, but the output and power supply stages are combined. Instead of creating a reservoir of power for the output stage to use, the DSP causes the power supply to actually create the output signal directly. Instead of running at a constant level, the power supplies are constantly going up and down (signal modulated) in response to the DSP to create the output voltage. There are no output transistors.
That's the conceptual picture, pretty much devoid of the details. At this point you may be thinking, "That's too easy" or "Why hasn't this been done before?" While the concept is easy, the execution requires a fairly powerful DSP, as well as a fairly powerful brain trust to program the DSP. On this scale (remember this amp puts out 10,000 watts), it also requires the planar transformers with specific coupling and power characteristics.
The DSP is in complete control of the transformers, running a constant pulse of 24kHz. That doesn't mean the transformers are creating a large 24kHz output signal, but that's the clock speed for the pulse-width modulation. When a signal comes into the DSP, it sends off/on pulses to the transformer switchers of the appropriate duration to create both the frequency and the amplitude of the output. In a pulse width modulation format the length of the pulse will correspond to the output voltage level, and in this amp the length of the pulses will be limited to 1/24,000 of a second. A maximum pulse (100 percent) will result in maximum power output, while a half-length pulse (50 percent) results in half power. At idle, there's zero current going through the transformers, but it's still happening at 24kHz.