Sony has always been a leader in high-value car audio products. This time we are going to have a look at one of their top-selling Xplod Series Class-D monoblock subwoofer amplifiers, the XM-ZZR3301. Rated at 330 watts into 4 ohms, and 600 watts into 2 ohms, the Sony XM-ZZR3301 sells for only $199.95, making it one of the best “watt per dollar” deals available!
The Sony Xplod XM-ZZR3301 amplifier, moderately sized measures about 14” x 11” x 2.25”. Stepping away from the traditional rectangular shape, the amplifier brings a bit of style to the mix with the ends of the amplifier being somewhat V shaped, and the upper surface of the cast aluminum heatsink offering some molded-in-design elements that add a touch of class and uniqueness. In the middle of the top of the amp is a large illuminated bar which lights up in a bright blue color when the amp’s turned on. All the connections and controls are along one side for ease of installation and adjustment. The connections for power and speakers are made via gold plated Phillips-head screw terminals. The power terminals will accept ring terminals that can be used with 4 or 8 gauge wire, and the amp is fused with
a pair of 30A ATC style fuses.
Four speaker terminals (although it’s a single channel, additional terminals are provided to aid in the parallel connection of woofers) will accept 10 gauge bare cable or 8 gauge with the appropriate ring terminals.
High level inputs are also provided if you want to provide signal to the amp from an existing amp or head unit speaker outputs, and these can be used as signal sensing inputs to turn the amp on when no dedicated 12 volt trigger is available. The high level inputs will accommodate amplifier power levels over 100 watts.
Control and adjustment features include what you’d expect; pots for gain, 6Hz-70Hz subsonic filter, +10dB of bass boost, and a 50Hz-300Hz crossover frequency adjustment.
In the interest of long term reliability, there are three different protection modes built into the Sony XM-ZZR3301, a thermal protection circuit first rolls back the power output as heat builds, allowing the music to continue, and a second mode eventually turns the amp off if the temperature becomes too high. Additionally, a short circuit protection mode engages if the speaker wires become shorted to each other or to ground. I also found another protection mode quite by accident during my listening…read on.
A peek inside the XM-ZZR3301 revealed a basic but well
constructed Class-D design. The double sided PCB places all the small signal surface mount parts, like the control IC’s, op-amps, and associated circuitry on one side of the board, and all the larger through-hole parts on the opposite side. This method allows the overall PCB to be made smaller without sacrificing area for copper traces. And it has plenty of copper for high current demands, and a heavy copper buss bar is used to augment current delivery to the power supply devices. The power supply itself is relatively robust, using a good quality toroid, and 6600?F of capacitance. The power supply switching devices are made up of six TO220 size Fuji MOSFET’s and are easily capable of handling the maximum current demand of the amp.
On the output side of things, the output devices are four N-Channel Fuji MOSFET’s and current is supplied via a total of 7000?F of capacitance. There is a large second order output filter to remove the Class-D switching hash from the audio. Overall, the design is clean and very well made.
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