So much for the exterior. Let's now look inside. Removing six screws allows the bottom of the amplifier to be exposed. The bottom plate is a relatively heavy sheet metal, and may be used to reduce spurious emissions that a switching amplifier can produce. The PCB is quite neatly laid out. It comprises mainly through-hole components. The board is a double-sided type. The PCB is approximately 5" wide and along its length run two vertically oriented aluminum sections. All of the power transistors are "clipped' to these vertical rails, and thus these form the basis for the heatsink. There appears to be 19,800 mF of B+ capacitance and a total of 12,000mF of reservoir capacitance on the secondary side of the power transformer. One strange feature is that the protection fuses are located internally (you have to remove the cover to change a potentially blown fuse). The power supply is controlled by the familiar and trusty SG3525 pwm controller chip. The core of the audio section is made up by a Tripath Class "T" digital audio amplifier chip. Class T technology is relatively new as far as switching amplifiers go. The technology differs from the more conventional and well-known Class D substantially. It is beyond the scope here to fully explain the differences, but simply put a Class D amplifier makes use of Pulse Width Modulation whereas the Class T amplifier makes use of a proprietary DSP chip to generate input signal dependent complex variable frequency switching patterns. That's a mouthful, but the goal is to offer the efficiency benefits of Class D technology while at the same time maintaining a high level of fidelity with high bandwidth. Overall the PCB shows good attention to detail and a nice absence of flying wires. Decent quality components appear to have been used.
DiscussionApart from output power the overall performance of the DPX is quite good. The only deviation from expected are the results obtained for the output power. They are substantially lower than the manufacturer's numbers; there appears to be no obvious reason for this. Input sensitivity range is fine and should not pose any problems for head units. The frequency response indeed indicates that the DPX1000.2 can be used as a full range amplifier. Even with a 2-ohm load the -3 dB point is well past 20 kHz that is just fine for full range operation. Signal-to-noise performance is good, showing better than -90 dB - good for any amplifier. To some extent, as expected, the damping factor is a little on the low side. This is probably due to the presence of the inductors in the low pass filters in the output stage.
The crossover filters exhibit a nice uniform response with no signs of peaking (under damped condition) or other misbehavior. The -3 dB points can be seen in the graph and can be seen to be not far off from the advertised numbers in the manual. The bass boost equalization curve is accurate: +15 dB at 45 Hz, exactly as stated.
Listening to the DPX was interesting. It was auditioned in full-range mode. The overall sound was relatively dynamic with a full-bodied nature to the bass sounds. The amplifier did a decent job of recreating complex passages. The midrange sounds were open. It was only in the treble region that the amplifier ever really struggled. This was only evident however when the amplifier was pushed hard. During these times the top end became harsh and somewhat muddled. Simply reducing the level a little cured nearly all of that condition.
The DPX 1000.2 is a well-built amplifier with a good feature set. It uses a relatively new technology to achieve both high efficiency and good sound quality over the complete audio spectrum. It could be used as the basis for a high-powered full bandwidth stereo setup, or for even higher powered subwoofer type applications. The only reservation is that the output power does not meet claimed specs, however, the power it does make is an exceptional value at $599.99 MSRP