Here's an amplifier that offers loads of power-we're talking bulk, economy, warehouse club power here! The price looks good and it's supposed to be an efficient Class D design, so let's take a look at what this much power will really cost you.
The Opti2000D is a discrete class D mono-block amplifier rated to make 700 watts RMS at 4ohm, 1100 watts RMS at 2ohms and 2000 watts Max at 11/42ohm. Total harmonic distortion (THD) is given as 0.1% at 1 watt, 4ohms. Lanzar has included exactly what you need for a huge subwoofer amplifier: a 24dB/octave lowpass crossover and 24dB/octave subsonic filter, phase reverse switch and dash-mounted remote gain control. If 2kW won't do the job you can strap two of these monsters together for an advertised max power of 4000-watts!
From the very first look at this beast you know it's an amplifier. The 19" x 10" x 2.5" extrusion is asymmetrically stylized with rounded edges, lightly grained and bright aluminum in color with a diamond cut 3D Lanzar logo and a black strip with the ID badges along one side of the top. RCAs and controls reside on one color-matched steel endplate while the power and speaker connections and six fuse holders fill up the opposite endplate. The bottom plate is also stamped steel, with louvers for airflow near the transformers, and mounting holes where the plate extends beyond the endplates.
The control endplate includes a Slave/Master switch and a Data Link port to strap a pair of Opti2000Ds across a single load.
Circuit DesignAlthough the Opti2000D is over 19" long, it is really packed full. The first thing you notice when you pull the cover off is the number of transformers and inductors spread throughout. There are two large power supply transformers with a dual secondary inductor, four small B+ filter inductors and two medium output filter inductors. The second surprise is the array of "hang off" devices - the transistors and rectifiers that hang off the sides of the main PCB so they can be clamped to the heatsink. It looks more like an A/B amp than a D, as class D generally uses a single pair of large output devices per channel. This one uses seven pairs-more on that later.
The power supply and output circuitry occupy approximately 16 inches of the 19-in amp, with the signal circuitry squeezed into an L shape at the end of the main pcb. There is very little separation between the signal and the output traces. This amp uses discrete class D drive circuitry on a vertical module rather than the more common class D configuration. There is a small vertically mounted fan between the module and the output inductors, but no shrouds or vents to define the airflow. The fan seems entirely useless to me, but even on my test bench I could not get this amp nearly hot enough to trigger the thermal protection.
Through-hole components are used throughout, even on the class D drive module. The main PCB is double-sided FR-4 with 2-ounce traces reinforced in a couple of places with 10awg jumper wires. Resistors are high-tolerance, and most of the capacitors in the signal path are film-type, all in all pretty high quality parts. Many of the large metal terminal blocks appear to have been problematic to solder in, with very little wicking (drawing of liquid solder through the holes to the top side) and visible "cold" joints. Cold joints are the result of having the solder hot enough to be liquid, but the part that is to be soldered is not hot enough to create a good bond. This is a common problem with large chunks of metal because they require a lot more energy to heat up than the tiny lead of a resistor or capacitor. While I expected this to be a problem on the power and output terminals, there was no evidence of power restriction even while drawing upwards of 125 amps on the bench. The only things that heated up much werthe power cables and speaker wires.