26 August 2008|
|Rockford Fosgate: Power T1000.4 Amplifier|
As the flagship model of the full range four channel amplifiers offered by Rockford for 2009, the Power Series T1000.4 is a very powerful, full featured amplifier that could easily serve as the only amplifier in a really high performance system. Very conservatively rated at 150 watts per channel into 4 ohms, and 250 watts per channel into 2 ohms, the T1000.4 can be used to drive front and rear full range speaker systems, or it can easily be configured to drive a set of front speakers and a subwoofer in bridged mode. Rated power in bridged 4 ohm mode is again conservatively rated at 500 watts x 2.
This amount of power usually requires a couple of amplifiers, but the engineers at Rockford Fosgate have come up with a way to shoehorn all that horsepower into a single chassis powerhouse. Measuring about 22” long, but only 8” wide and 2” high, the T1000.4 shares the same chassis size as the tremendously powerful T2500.1. In addition to the heatsink size, the T1000.4 also shares the 1/0 gauge power cable connections and the all new, and much improved speaker cable connections as well. Not only will the new connectors accept large gauge wire, but they hold the cables securely while providing minimum voltage drop. As an added benefit, Rockford Fosgate has listened to all the installers gripes about needing multiple tools to make the connections, and now these new models all use a single 4mm hex tool to secure the set screws.
Putting this much power in a relatively diminutive heatsink requires some skilled finesse with the thermal management system. The new Power Series amplifiers use an improved and refined version of Rockford’s DTM, or Dynamic Thermal Management scheme, which was first introduced in last years models. This shrewdly devised system takes maximum advantage of all the available heat dissipation available by placing the hottest operating devices where they will receive maximum heat transfer, and spreading the heat generated over the largest available area. Additionally, this technology includes a method of constantly monitoring the amplifiers temperature and operating conditions, and controlling the output current to provide longer playing times. What this means to you, the end user, is an amplifier that can be driven harder for longer periods without shutting off due to thermal protection, a common problem in high power four channel amplifiers.
Other changes that are new for ’09 are a pair of hidden-when-off LED based power meters on the top of the amp, that not only look cool, but give you a pretty good idea of how hard the amp is working. The meters use blue LED’s for the majority of the time, but turn red when the amp gets close to clipping, and you begin to hit the maximum power levels.A quick look inside the big four channel amp confirmed that Rockford was serious about power delivery, the PWM (Pulse Width Modulated) power supply uses eight large TO-247 MOSFET’s each capable of delivering 75A of current. The output stage is comprised of 16 more TO-247 devices, and get their energy from a bank of twelve 3300µF capacitors. Special vertical shielding boards keep the power supply noise away from the input circuitry, and like all Rockford Fosgate amplifiers, the T1000.4 makes use of very low tolerance surface mount parts throughout.
I installed the T1000.4 in my labs reference system, and as expected, the amplifier performed admirably. If you like your music on the loud side, but you still need low noise, low distortion, and great dynamics, the T1000.4 is sure to please. With the rear channels bridged into my 4 ohm woofer system, and the internal -24dB/Oct crossover set at about 80Hz low pass, I set the front channels to about 50Hz High Pass, and connected to my reference bookshelf speakers. A quick tweak of the gains balanced the system nicely, and a couple of dozen tracks later, it was easily apparent that the amplifier could easily generate all the oomph I could ask for and then some!
The sound quality was excellent as well, with a clean, articulate, and detailed top end from the front channels, even when the other half of the amp was pounding out the bass notes on my woofer system. During my listening, I did note that the amplifiers heatsink got quite warm, which simply means it was doing it’s job, of dissipating the heat generated by all those devices. I also found that the onboard Punch EQ system is almost a throwback to the previously patented Punch EQ, which was at least partly responsible for building the brands legendary sound way back in the ‘80’s. What’s different about Punch EQ? Well, for starters, it’s not just a bass EQ. While the Punch EQ does provide up to +18dB of boost at 45Hz, it also provides a bump in response at about 14kHz, which can help to overcome road noise and improve the intelligibility of the top end as well. After doing some careful listening, I came away with a very favorable opinion of the sound of the amp, although it didn’t sound quite as flat as my reference amplifier. I was later to discover during my bench testing that there are deliberate “bumps” in the T1000.4’s sonic signature that Rockford Fosgate believe make it a better sounding product when installed in any vehicle. And I would not disagree, anyone who has taken a look at the frequency spectrum of road noise in a modern car would notice that some judiciously placed and properly applied EQ could easily result in superior sonics.
On the Bench
After the listening portion of the test was over, I moved the amplifier to the test bench to see just what kind of numbers I’d get out of it. I expected the T1000.4 to exceed its power specifications based on my listening experience, but I had no idea they were to be not merely exceeded, but annihilated them! Actual measured power tests showed the big four channel amplifier produces over 230 watts per channel into 4 ohms, and an astonishing 380 watts into 2 ohms! Maybe you’d expect with all this power crammed into a smallish chassis, that you’d have to give up some signal to noise performance, but that is not the case. In fact, the big four channel Power Series amp measured better than many two channel amps, at an excellent -92dBA referenced to 1 watt of output, or over -116dBA referenced to full power. Stereo separation also measured very good at better than -50dB.THE CONCLUSION
As is usually the case with the majority of four channel Class AB amplifiers, the only spec that may leave you wanting a little is the efficiency, and the big Rockford four channel is no different, coming in at a bit over 65% at full 2 ohm power. But with this kind of power on tap, it’s kind of like driving a ‘60’s musclecar with a big block motor… gas mileage (or current demands) aren’t really foremost on your mind.