Sony XM-2252HX Amplifier Review
by Richard Podsada
The Sony XM-2252HX is a standard 2 channel amplifier, the largest in the Sony xPlod line. It's capable of delivering 225W x 2 RMS and 600W x 1 RMS into 4 Ohm loads. This amp features a standard set of controls (see Figure 1a, right). A continuously variable, 12dB / oct Hi/Lo pass crossover variable from 50 to 200 Hz makes it suitable for a subwoofer amplifier. There is also a variable Bass boost @ 40 Hz from 0 to +10 dB for a little extra thump in the lower range of frequencies. All controls are located in the front of the amplifier and are recessed into the casing, requiring a small flat screwdriver to manipulate.
Some unique features of this amplifier worth mentioning is the configurable twin-rail power supply, which may be switched between High Voltage / High Current mode (as with most other HX amplifiers). This allows you to make a tradeoff between output power and load handling stability in stereo and bridged mode (2-4 Ohm loads for High Voltage, 1-2 Ohm loads for High Current). Basically you can drive a load of half the impedance of the standard High Voltage ratings, at the same power, in High Current mode. It is not a feature to give you more power, but simply to make the amp more versatile (i.e. Lets say you have a 2 Ohm sub already and want to use it in mono - this amp will let you do that, and then drive a set of 4 ohm speakers as well).
Another component of this amplifier making it unique is it's fairly extensive set of diagnostic LED's (see Figure 1b, left) for it's built in protection circuitry. It will not only shut down the amplifier in case of an emergency, it will tell you why it shut down as well. There are 5 LED's on top of the unit which 2 are used to indicate which mode you are running in (High Current / High Voltage, only one will light), and 3 tell you the status of the amplifier. These bicolor LED's will go from green to amber to indicate a problem with your setup. They are labeled "Over Current" (you are driving too low of an impedance load or the speaker leads are shorted directly), "Offset" (the amp is generating DC current - you probably have a ground loop somewhere, check the amp mounting screws for grounding, and your power / ground connections), and "Thermal" (overheating). If all the lights are green, you are ready to ROC!
For connectors, the amp has standard RCA jacks for signal input, and a set of full-range RCA line-outputs for linking further amplifiers to it. There is also a set of speaker level inputs (see Figure 1c, right) which are small tab-insert jacks to keep things neat. Although, I don't like their contrasting blue/white look with the amplifiers body, they are small and serve their purpose well. The remote turn-on input is also of this type, and located in the back near the Power / Ground screw terminals. The Power / Ground terminals are the screw-down terminal type and will fit 4 gauge forked-spade terminals. Speaker output terminals are standard screw types. All speaker and RCA connectors are gold plated.
As far as aesthetics go, this is a big, beautiful amplifier. It's painted a rich metallic red, and has a very sleek look. If you like red, these amplifiers are definitely for you! The amp measures in at roughly 10" x 20 " x 2", making it a long, slim design. It weights (approx.) 11 lb. and all signal/speaker connections and controls are one end of the amp, the power/ground/remote connections lie on the other side.
Here is Sony's specifications regarding power output:
RMS Power Output @ 14.4V (High Voltage) RMS Power Output @ 14.4V (High Current) 225W x 2 @ 4 Ohms 225W x 2 @ 2 Ohms 300W x 2 @ 2 Ohms 300W x 2 @ 1 Ohm 600W x 1 @ 4 Ohms (bridged mono) 600W x 1 @ 2 Ohms (bridged mono)
As you can see, there is no gain from driving lower impedance loads in High Current mode, just the simple ability to do it at the same rated power, which is a unique feature to an amplifier in this price range. Also note that these ratings are all at 14.4V, which most of us don't have the pleasure of running. Most vehicles run at about 13.8V with the ignition on. You can do a simple Watt / Volt calculation to get an estimate of what the actual power output at 13.8V would be (note that this isn't very accurate and is just to give you an idea of what the ratings would be):
RMS Power Output @ 13.8V (High Voltage) RMS Power Output @ 13.8V (High Current) 215W x 2 @ 4 Ohms 215W x 2 @ 2 Ohms 285W x 2 @ 2 Ohms 285W x 2 @ 1 Ohm 575W x 1 @ 4 Ohms (bridged mono) 575W x 1 @ 2 Ohms (bridged mono)
You can expect somewhere around a 5% loss in power from the lacking battery voltage. If this amplifier had a fully regulated power supply it would perform at it's specs regardless of battery voltage, such as the ESX Quantum line of amplifiers.
Regardless of these probable losses due to battery voltage, this amplifier still has more than plenty of power to spare for most normal (non competition) applications and can floor out (2) JL 12W3's in bridged mono with relative ease.
Power Input / Requirements:
The amplifier requires an operating voltage between 10.5V and 16V, and will draw roughly 50-60 amps of current at it's rated power driving a 4 Ohm load in High Voltage mode. You can expect more current draw (60-70 amps) when driving lower impedance loads and large subwoofers.
Power input terminals will fit 4 AWG wire, although from a distribution block it is practical to run 8 gage to the amplifier. The remote input only draws 2mA of current, so that is a bonus when you are running a fairly high number of components strictly off of the head unit remote-turn on lead (which most have about 100-300 mA of current available). Although, I still recommend using a relay in this type of situation.
The RCA inputs will accept a signal between 0.2 to 4.0V, where the speaker level inputs will accept a signal twice that (between 0.4 and 8.0V). Using a line driver (such as the Phoenix Gold PLD) or a High Volt headunit (e.g. Nakamichi, etc) is not recommended with this amplifier.
Speaker performance (subjective SQ):
The 2252HX has a lot of power to drive speakers, more than most require. It has sufficient power for most 3-way speaker applications (e.g. Dynaudio System 340) in stereo mode. However, I found the noise floor of this amplifier (like most other Sony amplifier equipment I've used) to be very high, and to eliminate it completely you are limited to setting the gains on the amplifier to about 1/3rd of the maximum output. This makes the amplifier unsuitable for any sort of sound quality competition applications, but it is completely tolerable for the average system. You can expect this however, since this amplifier isn't exactly geared towards the high-end user, but to the everyday driver. Overall the amplifier has a very flat sound, and equalization is highly recommended. It does color the midranges and highs a little bit, but overall the performance is fairly standard. On a scale of 1 to 10 for speaker performance, I would probably give it a 6.
Subwoofer performance (Power / Control):
This amplifier is much better suited for powering subwoofers, due to it's simple set of features and high power output, as well as it's ability to drive lower impedance loads. I've tried the amplifier with (2) 12" Pioneer Premier TW-1240C woofers (200W) in stereo mode, and it can floor them out with no problems. Later on I used this amplifier driving (2) JL 12W3-D6's (250W) wired to a 6 Ohm mono load, and it was matched just about perfectly. I found less distortion driving the higher impedance load, and it worked out to give the subs just about 500W of power, so it was right on the money. Later on when I added the third 12W3, and wired them all in 4 Ohms, is when my performance suffered, due to underpowering the subwoofers (they required a total of at least 750W to run). This amp seems to be great for driving a set of (2) subwoofers which are each rated at about 200W or so.
As far as control of the subwoofers go, I was not too pleased with this amplifier. Although it has tons of power to dish out, it doesn't exactly do it as neat as one might like. I found myself always fiddling with my bass controls, crossover points, and an array of other things because a lot of the time I would get more boomy, sloppy bass than I would like to hear (when it comes to bass, I'm a perfectionist). Once again, it is suitable for a teenager that just wants to rattle his trunk around town, but it is not competition quality equipment. I found a lot of details lost in the distortion of the cone movement, so this is something to be noted if you are considering this amp and have an impeccable drive to achieve super-deadly tight-as-hell detailed bass with kidney-punching qualities (like I am). On a scale of 1 to 10 for subwoofer SQ and performance, I would give it a 6.5.
If you don't have a critical ear for bass, aren't nitpicking, or are using this with subwoofers in your trunk, then you should be very pleased with this amplifier. The trunk will hide most of the distortion present (it isn't that bad, but it's WAY more than *I* like). I ran this amplifier in a hatchback with woofers right behind the front seats so I could hear every detail of the sound present.
Installation / Manuals / Notes:
This amplifier has a standard installation procedure. Our amplifier installation tech article is more than sufficient to get you on your way (see the http://www.teamrocs.com/technical/).
As far as documentation for this amp goes, it is clear, concise and to the point. Easy to follow diagrams and lots of notes will help get you on your way, but remember to read our amplifier installation article if this is your first amplifier installation. There are some very important points and procedures for safe, well-performing amplifier installations in our article.
Notes: One common thing people seem to have problems with is the amplifier shutting down due to an "Offset" error (indicated by the "Offset" status LED glowing amber, see Figure 1b above). Almost 99% of the time, this is because the case of the amplifier is grounding through the mounting screws to the car chassis, or some other piece of metal below it. This creates a ground loop and the amplifier's protection circuitry seems to be sensitive to this scenario. I *highly* recommend mounting this amplifier on a board, then attaching the board to the car floor / mounting point separately. Make sure you don't drill into a gas tank or anything. Using rubber grommets in the amplifier mounting holes for the screws can help also, but is not always reliable. If this is not the problem (you already have the amplifier on a board/etc), then check your power and ground connections, make sure all connections are tight, and that your speaker terminals / leads are not grounding to the chassis either. Also always ground all amplifiers to the same point on the car chassis. See our amplifier installation tech article for more information and detailed instructions on how to do the job right, the first time.
Warranty / Pricing:
Standard Sony 1-year limited warranty. MSRP is $450.00. Street price is roughly $300 - $400 USD.
Overall rating / Final comments:
This amplifier is on the higher end of the medium-level priced amplifiers on the market today. If you are just starting out in car audio, have a limited budget, or just want to rattle some panels in the ghetto, then this amplifier is a perfect choice for lots of power and fairly good sound quality for it's class.
If you are competing, or have a competition-level critique for sound, this amplifier won't do the trick. Look towards something more high end, you can find lots of great deals on good used equipment on the Internet.
Overall rating: 6.5 (out of 10)
Sony Mobile XM-2252HX
Note: On their website, they rate the amplifier as doing 650W x 1 @ 4 Ohms mono, which is *incorrect*.