You have to do a lot of things right to stay in business these days. Pioneer is one of those companies that have been around for so long that we all expect it to be here forever.
To stay on top of the game, Pioneer has developed a new line of amplifiers using a technology named "ICEpower" (see story on page 34). Originally developed by the hi-fi home audio group Bang & Olufsen, it promises Class D efficiency with full-range sound quality. This issue we take a look at the PRS-D2000T, a full-range 150 watt x 2 (@ 4 ohm) rated amplifier using a supply design that Pioneer refers to as Class FD. While this is in essence a Class D amp, ICEpower offers a cool twist.
The PRS-D2000T sports a HP/LP/All-Pass 12dB crossover that ranges from 40Hz to 120Hz and a remote bass boost controller. The remote bass controller boosts the bass at 50Hz to four settings selectable from your dash - 0dB, 6dB, 9dB and 12dB.
Cosmetics
The amp is contained in a fairly elaborate aluminum casting covered in a semi-glossy metallic grey powder coat. There is a large "Premier" badge set in thick acrylic with a nice, contrasting blue background and a thin acrylic insert trailing off down the centerline of the heatsink. When the amp is powered, both acrylic pieces illuminate in a radiant blue. Just below that, and encompassing the lower half, is a second cast piece that shrouds all of the connections and controls. Overall this amp is a very good-looking piece that when mounted in your trunk, especially at night, will provide a nice look with its blue glow.
Layout
Inside the amp, the circuitry reflects the layout of the connections and controls on the outside. To the left end is the power supply; amplification is located in the center section behind the speaker terminals; and the low-level stuff runs back from the RCAs on the right end to the vertical daughter board that houses the crossover and gain circuitry. Pioneer uses a double-sided PCB with a combination of through-hole and surface mount components. The hang-offs run across the left end and the back of the PCB, bolted to cast aluminum blocks that are themselves bolted to the main chassis to complete the heatsink scheme.
Signal from a source unit enters the amp through a set of gold-plated RCA connectors on the right end of the amp. The "Preout" connectors next to the inputs are parallel with the inputs, acting simply as a "Y" connector to feed additional amps. Through the coupling capacitors to block any potential DC on the lines, the signal proceeds to the vertical daughter board, where it is gain-controlled and passes through (or by) the crossover circuits. The signal then proceeds to the surface-mount ICEpower ICC1 chip on the bottom of the PCB, where it is modulated and sent to the output stage.
On the left end, battery power comes in through ample Phillips-screw terminals, a pair of 30-amp fuses and a cap-and-coil filter before reaching the 1.5" ferrite core toroidal transformer. The coil uses really big flat wire (about 5mm across) that is flat wound through an e-style frame, and there are two 3,900F capacitors here. There are six 50-amp switchers controlled by a surface mount 494 PWM controller that runs the solid-strand transformer at 36kHz, resulting in available voltages of +42 and -38V for the outputs. The secondary side of the transformer is rectified and then filtered by a pair of inductors and 16,200F worth of capacitors. The high-speed, high-current output Mosfets are controlled by two ICEpower ICC3 surface-mount chips, which also provide feedback to the ICC1 control chip. The high-current output passes through another toroidal inductor (one per channel), a pair of relays and on to the speaker terminals.
Performance
The frequency response was a bit odd, to say the least. Although Pioneer states 10Hz to 40kHz at -3dB, the measured response was -3dB around 16kHz (per our test parameters, a result of 12kHz was taken at -1dB). This is fairly typical of a Class D design, though, because it has a big cap-and-coil filter at the outputs. Yes, it's the same as the ones you might use to build a passive crossover for your speakers, but this one is designed to lowpass at the top of the audible range, effectively converting the PWM waveform back into a sine waveform. As with all passive filters, the frequency response is affected by the load it is operating on (i.e., your speaker's impedance). I ran the sweeps with various load resistors across the speaker terminals (within the manufacturer's allowable impedances, of course) and have presented the best-case scenario. The thing about speakers is that the actual impedance will be different at different frequencies, so a resistor as a load may not present the same results as a speaker would.
The rest of the test results measured impressively close to Pioneer's specs, indicating tight tolerances and good quality control. The crossover came in at 12dB/octave with very little deviation from the 40Hz to 120Hz spec, although both the highpass and the lowpass crossovers added about 1.5dB of gain to the signal. The bass boost was exact at gains of 6, 9 and 12dB but centered at 48Hz instead of 50Hz. No, you can't hear that.
The over-current protection worked well, disconnecting the output relays and immediately "re-booting" itself so you don't have to turn off your system and turn it back on to get it going again. With the speaker terminals shorted, the amp just blinks and clicks off and on until you remove the short. Although the amp got scary hot during the listening test (it's already 110F here in Arizona!) it did not trigger the thermal protection. There was no turn-on or turn-off noise - well, except for the output relays clicking. Not sure how that would score in a competition, but I could hear the relays in the trunk from the driver's seat.
Manual
The owner's manual is the big "map" style folded sheet of paper. The instructions and pictures are good and straight to the point in three languages. There is an addendum concerning the gain setting that is in 11 languages, including 3 that don't use the Roman alphabet. That's got to be some kind of record! However, I was surprised that Pioneer didn't include the usual sales pitch explaining all the cool stuff you just bought, but at least they point out the warranty that covers the PRS-D2000T for two years, including parts and labor.
Conclusion
The Pioneer performed very well on the test bench, confirming the manufacturer's specs in all cases but one: the frequency response. I can hear that the amplifier plays well beyond the bench measurement. The midrange is excellent, but the highest frequencies sound subdued and flat, and the imaging is adversely affected as well. If you're as picky as I am about high frequencies and good imaging, you should consider this amp for use with subs or on midrange drivers in a tri-amp system where it can operate in its best range.
The retail price on the PRS-D2000T is $350.00. The maximum unclipped output was 554 watts, giving a dollar-to-watts ratio of 63 cents per retail watt. That's a pretty good price for an amp this good-looking with the latest technology. V
Listening
Taking some sanctuary from the desert heat, I loaded up the amp in my black LSE and connected it to the separates in the front doors for some impressions. I ran the Alpine Media Manager through its automatic time correction and Road EQ setup routines and settled in for some serious listening.
First up was Donald Fagen's Kamakiriad, as usual. I like to start here because it covers the entire tonal spectrum and reveals possible weaknesses that can be explored with other material. Anyway, I let "Trans-Island Skyway" run while I was looking for my pen and paper, and was surprised by the finger snaps running through the rhythm. They were right up front and clear, more so than I remember previously. Moving on to the usual "Snowbound" audition, the string buzzes on the bass guitar and the Fender Rhodes low crunch were very clear. So far, so good.
"Tomorrow's Girls" has some great cymbal work on it for evaluating the top end. The piano was more distinct than usual, but the cymbals seemed compressed or flat. The image was very low; it sounded like they were coming from the bottom of the dash instead of the middle of the windshield and was quite right-biased. I adjusted the balance toward the left a little, which centered the image left to right and raised it a little bit. Still it was quite low.
Sensing weakness in the upper ranges, I put in Mary Chapin Carpenter to see what would happen. Female vocals work well to spot phasing problems (both 180 degrees and slight shifts) as they are more complex. While the piano sounded perfect on "Only a Dream," Carpenter's voice was a little heavy sounding and again the image was low. The cello on "I Am a Town" was pretty good; again the piano was great and the vocal, average.
You gotta love music exchange stores. I recently picked up a favorite that an engineer friend liked to blast from the listening room during the day, filling the entire second floor with energy. Crystal Method's Vegas CD is one of the best road trip companions you could find, especially if you have a big system. So I gotta check it out on this Pioneer amp, right? It sounded pretty good, but the entire content is produced and processed electronically, so there is really not much to evaluate other than the "fun factor." Yeah, 10 points!
I reconnected the PRS-D2000T to my 12" dual voice coil sub mounted in a sealed box and continued with Crystal Method. Still fun, but back to work! Next I loaded in Bass Mekanik (I love this job!). The Pioneer responded to the deepest sine bombs at the lowest frequencies, not missing a thing. It wasn't as quick and transient as my reference system on the sines, but definitely better than the usual Class D design.