Xtant rates the output power of the 1.1i at 100 watts into 4 ohms and 100 watts into 2 ohms. That's not a typo, and it grabbed my attention, too. Current limiting to keep the amplifier operating within its optimum range? Perhaps. Rail switching, like some other Xtant models? Maybe. Xtant also claims a frequency response of 17Hz to 20kHz, +2dB. Seems a bit ambitious for a Class D.
CosmeticsAs I mentioned, the 1.1i is a 100-watt mono amplifier, so I received a pair of them for testing. They arrived in boxes seeming to contain more air than amplifier. Of course you probably think I am kidding, yet at 6.5"L x 5.81"W x 1.63"H (about the size of a 20-disc CD wallet), these amps are unbelievably small. However small, though, these guys are surprisingly weighty.
On one side of the amplifier are three fins, part of the black, extruded aluminum heatsink. Atop the black heatsink is a polished stainless steel cover that immediately proclaims, "I am Xtant!" The power, speaker and input connections are all on one side, accompanied by the gain control and an electric blue power indicator LED. It is clean, classic and unapologetic in appearance. When you take the cover off to gain access to the mounting screw holes (wrenches and screws provided), the "Black Box" mystery continues inside, where Xtant purposely removed part number markings on the ICs.
Design and LayoutAll the connections are on the front of this amplifier and the flow from the power side to the signal side makes good sense. Battery power enters through terminal blocks large enough for 4awg cable on the right-hand side of the panel and runs straight back to the primary caps (3000F total) and on to the switching devices mounted to the heatsink. The transformer is a little forward and to the right, while the rectifiers and thermal sensor occupy the center area of the heatsink. Signal input is front and to the left of center, adjacent to the speaker outputs, which are capable of handling 8-gauge cable. The output FETs are on the left side of the heatsink and feed the output filter directly forward and on to the output terminals.
Xtant uses little standard circuitry in the 1.1i. The input section isolates the ground (or shield) side sufficiently to treat it as the negative side of a balanced line input. The negative side ultimately runs into a differential amplifier (op amp). Even if you don't have a balanced line source unit there are at least three advantages to using it with standard RCAs. First, the signal clarity and definition is much greater. Second, most of the noise that can be radiated into your signal cables will be eliminated through common mode rejection. Third, you can connect virtually any head unit directly to the amplifier.
Nearly all of the components are surface mount, even some of the large resistors, lending itself to tighter tolerances. The board itself is double sided, and there are no jumpers or buss bars present. All of the components are on one side of the board, and everything is tight and neatly laid out. We applaud Xtant for using 105-degree C rated capacitors in both the primary and secondary portions of the power supply rather than the more common 85-degree C caps that, because of heat, degrade more quickly over time.