31 August 2008|
|Rockford Fosgate T2500-1|
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Inside the T2500-1 is a twin toroid power supply that uses no less than twelve Fairchild TO-247 case size N-Channel MOSFETs, each rated at 75A, and there are another eight TO-247 size International Rectifier HEXFETs in the output section, rated at a minimum of 30A each, giving the output of the amplifier a conservative current output capability of 240A! Lest you think the amp is all brawn and no finesse, I should direct your attention to small but important details, such as the use of top quality FR-4 double- sided plated-through glass epoxy circuit boards, high speed polypropylene capacitors, and there is even a special vertically mounted board that is designed to shield the sensitive input circuitry from unwanted electromagnetic interference caused by the power supply.
The vast majority of the parts used are surface mount type, and in the case of the dozens of resistors, they are all 0% tolerance surface mount type, which increases reliability and reduces performance differences between serial numbers.
The T2500-1 comes complete with a full suite of features that you’d expect on an amplifier of this type. The input gain sensitivity has an adjustment range from about 200mV to over 5V, which provides over 28dB of adjustability. Crossover control is handled by a fourth order (-24dB) network, and is adjustable from 35Hz to 250Hz. A -12dB per octave switchable subsonic filter is also included, which, when engaged, rolls off the very lowest frequencies beginning at about 28Hz. Additional signal control is provided by a 0-180° phase switch, and the Single/Master/Slave switch which allows you to configure the amplifier to suit your particular system design. As with virtually every amp Rockford Fosgate has produced since the earth cooled, the Punch EQ is also along for the ride. With as much as 18dB of boost at 45Hz, and a properly configured filter Q, it’s easy to dial in the amount of “help” needed to make up for old recordings, or road noise masking the bottom end. A remote version of the Punch EQ control can be added to the amplifier to allow you bass EQ adjustability form the driver’s seat.
In terms of measured performance, the Power T2500-1 bested all of its rated power specifications, delivering well over 3kW into a 1 ohm load. While S/N specs are seldom great in these types of amplifiers, the T2500-1 posted a respectable -65.8dBA number, measured at 2V of output. Efficiency was very good, at a touch over 83% at full 2 ohm power, and still maintaining better than 74% at 1/3 power. That said, you have to understand that even with great efficiency numbers, delivering over 3000 watts of power is going to take a pretty stout electrical system, the maximum current demands of this powerhouse were 310 amps!