Serious sound quality enthusiasts have long been singing the praises of Precision Power amplification. Back in the early days of autosound contesting, Precision Power was one of winningest brands in the sound quality wars. Well, that history and performance has not been forgotten, and although the brand is under new ownership these days, the song remains the same. One of the most popular models is the PC640.4 four channel amp, and Grizz Archer, the Product and Marketing Manager for Precision Power, sent me one to check out. The PC640.4 is rated at 115 watts into 4 ohms and 160 watts into 2 ohms per channel. Here in the U.S., it has a suggested retail price of about $450 bucks.
The PC640.4 is designed primarily for exceptional sound quality. To that end, the engineers have done things a bit differently in the circuitry of the PC640.4. Beginning with the ability to accept true balanced input signals from Precision Power’s optional Balanced Line Transmitter, to the low current and differential drive stages, to the use of expensive but high performance poly-type capacitors in the input section, it’s obvious someone really cares about how this thing sounds.
The amps physical size falls into what I would consider the moderately large category, measuring 16.75” long, 10” wide, and 2” tall. Fastened to its mounting surface by four ingenious feet with protruding tabs that fit into special openings on the ends of the amp, once mounted, the amp can be removed by only loosening 2 screws. Continuing the quick release concept, the speaker, and power connections are accomplished via removable spring loaded terminals. I’ve used these before, and I have to say, although convenient, I’m not a big fan of them simply because they don’t accept large cables readily, and the wires can be difficult to secure. But they do have some cool factor, and once connected they work fine, but give me a traditional terminal anytime.
The fit and finish of the PC640.4 is very good, with the smooth, oval shaped heatsink finished in a refreshingly different pearl white with a nice brushed aluminum center strip. The amp looks classy and more expensive than it actually is. All of the connections and controls are well marked and easy to read.
Speaking of controls, the PC640.4 has a ton of flexibility and adjustability. One pair of channels can be run in an all pass or high pass configuration, while the other pair of channels can be configured as all pass, high pass, low pass or even bandpass. High pass crossovers are adjustable from 15Hz to 4kHz, using a range multiplier switch. Low pass frequency selections are from 50Hz to 4kHz, and if you engage them both, you can create an adjustable width bandpass filter. This flexibility allows great control if you prefer an all active crossover system, whether you’re connecting mid-bass drivers, or tweeters. All crossover slopes are fixed at -12dB/Oct. Other features include a 2/4 channel input summing switch, and Bass EQ for channels 3+4, with variable frequency, from 30-90Hz, and up to 12dB of boost. A single dual-color LED informs of power on or protection events.
Taking the bottom off the amp, inside I found a nicely laid out PCB, with a pair of transformers, a good amount of capacitance onboard, and large case high quality devices throughout. As I mentioned earlier, the front end uses very good quality capacitors, and an abundance of surface mount parts insure very close tolerances. The board was clean, with no kluges or afterthoughts.
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