Ultimate Sound DT2-800
www.ultimate-sound.com

Ultimate Sound introduces the competition scene to class T technology.

The DT2-800 is a two-channel, full range, switching amplifier with power ratings of 200 watts x 2 or 800 watts x 1 into 4 ohms, and 400 watts x2 into 2 ohms. Features include defeatable high and low pass filters with variable cutoff frequencies, variable bass boost, 12 dB input pad, and RCA line level outputs.

Performance
Ultimate calls this bad boy a class T. While I’m not sure what happened to most of the classes E through S, there are a few things that are obvious; it’s a switching amp, it’s capable of full range operation, and it seems to operate reasonably well. As one might expect, there’s a fair amount of switching noise on the amp’s outputs. However, it’s well above the audible frequency range and the amp will actually reproduce 20 kHz with a good amount power. This would put it on the “exceedingly rare” list and ranks it as a first for this reviewer.

When measuring the power response of an amp that has a substantial amount of ultrasonic noise, a compromise or two has to be made. The input to our distortion analyzer is filtered during such a test. This rids the measurement of high frequency noise that would otherwise cause artificially low results. The catch is that if you filter too much, you don’t get an accurate measurement of output power at high frequencies. With our standard power response test, the DT2-800 only managed about 150 watts x 2 at 1% THD+N into 4 ohms. However, with a little filter manipulation, things fell into place. The amp still came up a bit short of it’s 2-ohm rating, producing about 350 watts x 2 through most of the audio bandwidth, with a minimum of about 260 watts x 2 @ 20 kHz. Bridged output into our 4-ohm reactive load measured an impressive 952 watts, although the internal protection circuit triggers just after the amp begins to clip.

Efficiency at 1/3 power measured 63 percent, and efficiency at full output measured about 70 percent. In other words, about the same as class D with full range operation thrown in as a bonus.

Connections & Adjustments
Connections to the DT2-800 include captive style terminal blocks for power and speaker connections, RCA inputs and RCA line level outputs. Power and ground connections easily accept 4-gauge bare wire while speaker connections will handle slightly larger than 8-gauge wire. Adjustments include input sensitivity (with a 12 dB pad), bass boost (0 - +18 dB @ 40 Hz), high pass filter enable and cutoff frequency adjustment, and low pass enable and cutoff frequency adjustment. Both filters have a cutoff frequency range of about 50 Hz to 5.5 kHz.

Installation
The DT2-800’s input section provides flexibility in a very straightforward manner. The internal crossover is a three-way unit capable of low pass, high pass, or band pass operation. The addition of the 12 dB pad on the input sensitivity control also increases installation flexibility by allowing the amp to be matched to a wide range of input sources. All of the controls are arranged sensibly — everything works much as one might expect, and the overall construction appears to be both hefty and well thought out. These days, that’s no small compliment.

Of course, the big question is, what are the major advantages of a full range, switching amplifier? The DT2-800 gives the consumer another, more efficient choice that they didn’t have before. Like an A/B amplifier, it can be used to power an array of applications, including subwoofers, mid-woofers, midranges, tweeters, component sets, coaxials, or any other full-range or bandwidth-limited application. The current batch of Class D switching amps are limited to powering subwoofers, and, as we’ve said many times, a class A/B amp in this power range is a huge current hog that’s unlikely to meet its full potential with a wimpy automotive charging system. With a more efficient design, you’ll get closer to that magical kilowatt of output under real-world conditions.