Pioneer PRS D420

Compact amplifier with repositionable top plate, such that it can be mounted 180 degrees either orientation with logo reading correctly but keeping all the connections on the side the installer prefers. Secured by stubby Allen headed bolts. Hidden beneath this is the simple crossover array. Despite being a greater than half kilowatt capable product the subsonic filter is fixed frequency and is not defeatable, with no visible controls. Uses the same op amp as the DEH-P88RS headunit for greater high end compatibility. All speaker and power terminals are grub screw type, gold plated, angled at 45 degrees to the panel for greater ease of use and are Gold plated. There are four RCA inputs and one pair of bypass outputs. You can set the amplifier to accept high level inputs from the RCAs by use of the supplied RCA-to-speaker-wire adapters and appropriate switching. The amplifier will signal sense to switch on via this speaker level input once set. Simple multi-position switches used to select crossover status. Shiny and attractive in appearance, the top panel has a small inset plastic logo-plate with a slot window that the power-on LED indicator shines through. Runs in class FD, said to be superior to Class D, with licensed icePower digital circuit topology.- Class FD (Full range Class D) icePower MOSFET digital design for greater efficiency and less distortion
– 4 x 75w RMS @ 4 Ohms
– 4 x 150w RMS @ 2 Ohms
– 2 x 300w RMS @ 4 Ohms bridged
– Cast powder coated Aluminium heatsink with rectangular slab brushed aluminium top plate blue backlit logo showing through
– 8Ga. Gold plated power terminals with Allen headed grub screw connection
– 4Ch RCA input which also allows speaker or high level input via RCA to wire adapters, plus 2 RCA link output
– 12dB per Octave High/Lowpass crossovers 40Hz to 500Hz
– Subsonic filter, frequency not quoted
– Input sensitivity: 400mV to 6.5V or switchable to 1.6V to 26V via RCA to speaker-cable adapters (supplied)
– Stereo & bridged operation
– Frequency response 10Hz to 40kHz
– Signal to Noise Ratio >100dB
– Channel separation 70dB
– Fuse Rating 30A x 2
– HxWxD(mm) 56 x 304 x 195mm
Review by Adam Rayner
This amplifier is hot property and was a Talk Audio exclusive first review before any other publication got hold of it. It’s part of the Pioneer PRS high end line that has their incredible Pioneer ODR product as their big brothers. The make-it-louder circuitry is a licensed concept called icePower and is named FD or full range Class D. This is about combating the normally poor sound of class D amplifiers – up until recently only really used for bass amps that didn’t need to worry about high frequency fidelity – and while keeping the incredible efficiency of this sort of amplifier (so important in our limited-current automotive world where your alternator is all you got) so that you get as many watts as possible from the power you do have, you get a much higher fidelity sound.
I was worried at first that a channel wasn’t working but it turned out to be an issue with my test rig, which I soon fixed – it was an RCA connection thing.
The amplifier is a bit reminiscent of the Alpine Power Density or PDX series in that it has a big output of high quality and it is housed in a small space. In this case an ‘H’ shaped cast Aluminium chassis with a big sexy brushed Aluminium plate sat right on the top of it in a sunken shaped panel area. This plate has a slot with a plastic insert underneath that neatly marries up to the blue led ‘on’ indicator that sits right in the middle of the cast chassis’ top surface.
One lovely feature is that while all the connections are along one drop (with the signal inputs kept as far away as possible from the speaker and power connection points, of course) the top plate can be removed and replaced 180 degrees around. This means that the installer can choose which way around to put the connection side without worrying that the brand name plate will be on the wrong way up once its done. All held together by Allen headed bolts, it looks very smart and Japanese-high-endy.
Underneath the plate is where you find the crossover controls, which again, it has to be said are pretty basic. Like some of the others here, though, I feel these are only really on there as their lack would be noticed and perhaps as a safety net to prevent speaker damage by say bass being sent up a tweeter, against the mischance of someone switching all the Digital Signal Processing crossovers in your Pioneer head unit off by accidental cock-up.
The sound was big and bold, as befits something of the undeniable high price of this amp and played lots of detail but was just not quite as sweet as some of the more esoteric Class AB designs. It was truly impressive just how high quality the output was for the size of the product and how much muscle it seemed to garner for the power it used, as throughout all these tests I had both the Odyssey battery supported by the clever marine charger that Merlin Equipment sent us and also had the StreetWires power looms that BBG provided pierced by the probes of my multimeter with Volts DC showing in the right range in the display. This was so that no amplifier ran on anything but as vigorous and potent a 12V supply as possible. If it ever fell below 12V, I would pause for long enough for the battery to fill up a bit again. (Which is has to be said the Odysseys do with astonishing speed, so high is their inrush current capability.) The AudioControl SA-3055 registered 124.7dB at full-on levels without distortion.)
I got the distinct impression that the amp would work best with Pioneer’s own flavour of high resolution speakers and also that the right headunit – a DEH-P88RS would be the one to use as their electronics match the amp’s by design. At this level there is an element of voicing becoming relevant and this is serious Japanese engineering. The Nipponese high end world is one of astonishing detail and intricacy, whereas I was brought up partly on sweetness and the warmth of analogue valve amplification. Valves are still cult stuff amongst the high end boys and Panasonic once made a double DIN headunit with a valve (or vacuum tube) inset within the front panel that was found in a military parts factory and used for a special high quality head unit run. So Japanese engineers understand that side of things too.
Thus the sound, while being incredible for a better-than-normal Class D design – class FD – and being an obviously cool and clever thing for Pioneer to have licensed for car use, is not the biggest selling point. What matters here is that in real world cars, with real world sound-to-light issues with headlamps, who want to play their high quality systems as long as possible and as powerfully as possible at social events and stuff, this amplifier will enable the owner to do it for far longer than his mate with conventional amps.
It’s another case of a clever approach to a real world situation, along with a fatter slice of sound quality than one could ever have hoped for at the price and functionality level.
This is likeliest to sell to the dyed in the wool Pioneer fan but no one could ever tell you it was a bad idea if you got one but were not a full on Pioneer brand-o-phile. If they did you could just play it to them and blow them away with clarity-fed tunes. I like this a lot.
Overall 8.0
Sound Quality 8
Power Output 8
Features 7
Build Quality 9
Value For Money 8