Grand Four-Channel Ampfest
Welcome to another Talk Audio never-been-done job! Yes, another absolutely huge group review.
Not just bigger than any other publication anywhere – virtual or otherwise – ever gets to do (which speaks of a towering arrogance on my part maybe) but done to the depth that other magazines would invest only in a top-slot solo review.
Just for LOTS of product.
The work load is bizarre but I absolutely live for this stuff. The only real difficulty is gouching out and just starting to enjoy listening to music instead of being critical and carefully attentive as what this review is all about is the differences in sound between amplifiers. That can be subtle. Or all too horribly obvious – see the Koac ‘amp’ .
All car radios have got small amplifiers in their guts and once they had graduated from the horrendously complex and expensive things that were used in the old days, to the relatively easy power of the cheap transistor, (can you believe that early fitters sometimes had to remove a car’s heater matrix to fit a radio? Don’t even ask&$$.) it was thought for the longest time that radio was as loud as it need be in cars.
However, these days the world is well supplied with separate component amplifiers for cars and one of the most important categories of these is the one that can do everything (and often more) that the original thing in your headunit could do. Which is make four channels louder at once.
There are those that think an amplifier is an amplifier and as long as it says the right number of watts on the outside (and more always seems better to these folks) then surely they all sound the same?
Well they don’t.
The Big Thing is what you call signal to noise ratio, or how far into the background is the hiss. All electronics will add noise (hiss) to the sound, it’s just that the very best ones will have it so far back into the background that you cannot hear it. Even when the sound level is ball-blasting. Dynamics or snap or how loud versus quietly an amplifier can play is another factor. So far both these specifications apply for both head units or source devices as well as amplifiers but distortion is the biggie for amplifiers.
As amps run out of the ability to make ever yet more watts, they can begin to sound less lovely than they were at low stress. There are dozens of forms of audio distortion. Total Harmonic and Intermodulation are the most well known types. Basically you want as little as possible.
What we have done for this review is to gather eighteen amplifiers up and group up them into Affordable, less than £200. Then Mainstream £200 to £300 and then Posh, above £300.
Here are the amplifiers we gathered
AFFORDABLE (no particular order)
Kicker ZX 200.4 £199.99 4x35w RMS @ 4 Ohms
Clarion APA4360 £199.99 4x90w RMS @ 4 Ohms
SPL Dynamics S2604 £199.99 4x65w RMS @ 4 Ohms
Diamond D1 300.4 £199.99 4x50w RMS @ 4 Ohms
Blaupunkt Velocity VA475 £182.99 4x75w RMS @ 4 Ohms
Sony Xplōd XM-4S £199.99 4x50w RMS @ 4 Ohms
MAINSTREAM
Massive P400.4 £249.99 4x100w RMS @ 4 Ohms
Mutant Ascension 4 £289.99 4x85w RMS @ 4 Ohms
Vibe BlackBox Stereo 4 £299.99 4x110w RMS @ 4 Ohms
PowerBass ASA 600.4 £249.99 4x100w RMS @ 4 Ohms
MTX X-Thunder 704 £250.00 4x70w RMS @ 4 Ohms
Genesis Profile Four £299.99 4x70w RMS @ 4 Ohms
Harman-Kardon CA470 £250.00 4x85w RMS @ 4 Ohms
POSH
Tru Technologies Steel 44 £549.00 4x65w RMS @ 4 Ohms
DLS Ultimate A4 £799.00 4x85w RMS @ 4 Ohms
JL Audio 300/4 V2 £400.00 4x75w RMS @ 4 Ohms
Pioneer PRS D420 £399.00 4x150w RMS @ 4 Ohms
Hertz HP4 £749.99 4x130w RMS @ 4 Ohms
And here’s how it was done:
A ‘Known Good’ head unit was played through JL Audio RCAs to the test amp’s RCA terminals. Power to headunit and amplifier came from an Odyssey PC925 super-duty battery supported by a 10A marine high current battery charger. Speaker wires were by Esoteric Audio and StreetWires power cables and power distribution and fusing were supplied by BBG. A voltmeter was placed across the power system so the voltage could be monitored while running. Music was The Spirit of Sound #6 from Focal – a mad test disc with some kicking and funky material with fabulous recording quality. The SA-3055 RTA/SPL meter from AudioControl (as sent by the boss of AudioControl himself for our use) was applied to the rear of the test room on a tripod on a window sill that even the cats can’t reach in the stairwell, so as to ensure repeatability throughout all the eighteen amplifiers. Loudspeakers were a set of Morel Supremo 6 Components enclosed by the distributors and also a set of secret brand but ‘Known Good’ high power 6x9s in enclosures made by the old Fusion Area 51 facility.
The level was wicked up until audible difficulty was discerned then turned back to a level where it could be deemed as loud as it’ll go by ear. On this bit, you have to trust me and my asymmetrical-upon-my-head-and-pointy ears.
link
The embedded vid shows my early forays with this rig, playing a totally mint CD that Bowers & Wilkins gave me, thus proving they are utterly Cool. Mudbone’s Fresh Mud. I didn’t use it for the reviews but be aware the camera’s microphone starts to hurt above 98db and it was loud. The distortion and horrid noises are solely artefacts of the recording process – note the clarity in the quieter moments. It was about supporting these amps as if they were on a system in a car with an engine running so as to provide them with a better running voltage.
It’s daft but effective.
Apologies for how long it took folks but here are all eighteen now. Standouts amongst the affordable ones were the Clarion APA 4360 and the Diamond Audio D1, both well built and fabulous sounding for the money asked and well deserving of their Talk Audio Recommended status.
Of the Mainstream group, the best were the Vibe BlackBox Stereo 4, getting a Best Buy flag and the Harman Kardon CA470 winning a Recommended rating.
Of the Posh ones, the Hertz HP4 and JL Audio 300/4v2 both got Recommended ratings and we even had one State of the Art offering in the shape of the DLS Ultimate A4. That said, they will all have their fans and there wasn’t a true dud amongst them, which was nice…
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I hope you find it useful.
Adam Rayner :-))))