Mobile Electronics Australia

Their KS-AR8004 4-channel amplifier has been designed to emulate this feat, taking aim on the benchmark set by Alpine with the PDX-4.100 in the ‘power density’ ultra compact amplifier class. 

RRP for the KS-AR8004 is $629, which compares to the PDX-4.100’s RRP of $799. In typical JVC tradition, however, they’ve endowed the KS-AR with not only more power than its rival but with more features as well. But let’s kick off with its appearance and installation smarts. The KS-AR8004 comes in an extruded aluminium chassis that is finished in beautiful smoked chrome. The dimensions are very compact given its specific power output of over 500WRMS total, measuring 250mm wide by 182mm in length and just 62mm in height.

That means this amplifier will squeeze into just about anywhere. What’s more, JVC supplies a set of cast alloy brackets that allows multiple KS-AR amplifiers to be stacked on top of one another other. Since all three models (JVC also offer a mono and a 2-channel stereo) are identical in size this allows for mixing and matching types while keeping a symmetrical installation layout. This idea is a straight copy from Alpine’s PDX range, but the KS-AR amplifiers differ by being able to be installed when flipped onto their ends as well. Interestingly, this idea has subsequently been copied by Soundstream.

Assisting with neatness even further are connections made along the lower leading edge of the amplifier’s chassis, with nice 45-degree angled insert terminals for all power and speaker connections (4-awg and 8-awg respectively), while deeply recessed RCA inputs ensure that cables don’t protrude in an awkward manner. This is all very well thought out, and all of the markings are very clear so that you don’t inadvertently stick the wrong wire into the wrong hole. You also get RCA pass through terminals, allowing you to daisy-chain extra amplifiers when the signal source lacks extra outputs.

The top of the chassis features a deeply chromed square badge that’s screened with the JVC logo, and this can easily be unscrewed and rotated to ensure the logo faces the correct way no matter which way the amplifier is facing. Similarly, JVC provide a chromed concealing panel that covers all the amplifier’s controls and switches that are located on the opposite end of the chassis to the connection side.

Here JVC have used their smarts once again, and instead of finicky little dials that require a miniature screwdriver to adjust they’ve given us some nice fat plastic knobs to do the trick – making the settings quick and easy. The KS-AR8004 has a variable bass boost of between 0 and 18dB at 45Hz, variable input sensitivity of between 300mV and 6VRMS, and a choice of HP, full range, or LP output for each pair of channels. The filter slope is a nice steep 18dB per octave and the filter range spans from 30Hz all the way up to 500Hz.

JVC decided to optimize the power supply so that the amplifier makes the bulk of its power into 4ohm stereo loads, so don’t expect it to increase power significantly into lower impedances. The KS-AR8004 produces 120WRMS per channel into 4ohm loads or 130WRMS x 4 into 2ohm loads. This also equates to 260WRMS x 2 when bridged, though JVC expects that you’d use the matching KS-AR8001 mono if you wanted to power some subwoofers.

Squeezing 520WRMS from such a small package was no easy feat. The KS-AR8004 features no less than eight daughter PCB boards mounted at parallel or at right angles to the main PCB to conserve space. These facilitate the aspects not associated with high current or heat, like the input stage and the pre-amplifier functions. Likewise, further surface area is saved by flipping the power supply and output transistors onto their sides to stack vertically along the side walls of the heat sink. Nice stuff like surface mount technology (SMT) devices abound inside, while the actual arrangement and packaging of the hundreds of internal components is quite amazing to behold.

Road test

On a sound quality front the KS-AR8004 sounds absolutely fine, which means I’d doubt highly that you’d hear any difference between this and any regular old Class-AB amplifier in a blind A/B/X test. I was certainly very happy to listen to it for a few weeks in my test vehicle. It turns on and off silently, makes no audible anomalies, and most importantly it makes more than enough grunt in stereo configuration to avoid clipping distortion. The one caveat is that I really think this amplifier is best suited to powering full range speakers, since 260WRMS really isn’t enough grunt for subwoofer duties given today’s low efficiency subwoofer design trends.

Conclusion

The KS-AR8004 4-channel amplifier carries on JVC’s time honored tradition of offering buyers the very latest technology at a keen price saving over market rivals. The KS-AR8004 has obviously been designed to offer at least the equivalent in build quality as Alpine’s PDX-4.100 - yet with more useful features along with a dollop of extra power. From every aspect this amplifier screams great design. Dare I even say this is the first amplifier from JVC that buyer should lust after? It certainly deserves to be. The KS-AR8004 isn’t just great amplifiers by JVC – it’s a great amplifier period!