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Not unlike every industrial sphere, car audio has its illustrious leaders — audacious companies unafraid to reinvent the wheel if that’s what’s required to achieve the goal. Of course this ideology is not always proof positive of a true innovator. Development of new technology is critical, yes, but it sometimes requires significantly more acumen to do the opposite — that is, rather than head back to the drawing board, instead take an existing design and successfully infuse the latest technological advances into said platform.
It was this ideology that French master designer Focal had in mind when it began development of its new range of amplifiers. It didn’t look to reshape the world. Rather the ambition was to the take the highly successful FPS range, give it an aesthetic makeover and implement some technical updates. 
I suspect, however, that poor Focal is afflicted with a condition that might be labelled ‘techno OCD’. Not long after the project was initiated, things got a little out of hand, with the rejig soon evolving into a major rework covering just about everything from look and feel through to class and power. The efforts did not go to waste. The result is a new FPX range that looks absolutely stunning, and comes with power to match.
High five 
The FPX stable boasts many a configuration and we’ve tested numerous examples hitherto. Here we focus on the FPX5.1200, as it combines all the important facets necessary for a high quality budget amplifier, boasting superb power and efficiency, a small footprint, impressive performance specs and not too alarming a price tag; it’s one little power-house to be reckoned with. Using ‘digital’ switching Class-D topology, the FPX5.1200 is a quintuple-channel amplifier, outputting 75 watts continuously from its four satellite channels when measured at four ohms, while the subwoofer channel outputs 420 watts at four ohms. When loaded down these figures rise substantially, to 120 watts per satellite channel and 720 watts on the subwoofer channel respectively. However if you’re planning on taking the latter impedance path, ensure you have adequate airflow for cooling, because she can get a tad warm and you don’t want to dehydrate the caps over time. 
Total harmonic distortion remains at 0.03%, this measured at a healthy volume too, rather than at near-on idle as some less scrupulous manufacturers quote. Damping factor likewise stays quite high, thus ensuring controlled cone deceleration, while a decent slew rate ensures controlled reciprocation speed and accuracy. 
A signal-to-noise ratio of 75dB affords the ability to play fairly quietly so far as induced hiss and artefacts go. 
Just a word on power ratings before we move on — as some have queried how Focal arrived at those output points. It’s actually a perplexing conundrum deciding what power output a new amplifier design is to afford, not only because you don’t know what subwoofer the end-user intends to marry up to it, but also because you have other external considerations such as fiscal restrictions and real estate requirements. Sure, five figures of power output in conjunction with an equally imposing price-tag is fine — right up until you actually try to sell one. Focal is no Johnny-come-lately, and at the risk of overusing my clichés, this isn’t its first rodeo. It has carefully chosen the power output point, and this becomes self-evident when you begin to deal with as many subwoofers as this author does. The vast majority of subwoofer motors tend to hover within a certain band of power requirement, and most five-channel amplifiers tend to be either woefully inadequate or else titanically overpowered for what this band stipulates. Therefore Focal wisely chose the aforementioned 400 to 700 watt region, as it’s right slap bang in the middle of what ninety-nine percent of subwoofers require. 
It’s almost as though it’s done this whole amplifier gig before...
Making the connection
Turning to the presentation, the FPX5.1200 is an ultra-clean design — refreshing because, as much as I love Focal, the previous FPS range looked more like a Star Trek prop than a power amplifier. The new design uses an outer extruded aluminium case, anodised black for a very professional look. 
As mentioned the dimensions are anything but large, measuring a mere 337mm x 176mm with a height of 57mm, and a weight of 4100g. These physical dimensions take into account the plated terminal blocks recessed into the ends for protection too. 
At the business end are 4AWG power and earth terminals along with the operational LEDs and five sets of speaker outputs able to accept up to 10AWG cable. The other end of the unit is home to the three plated RCA input pairings, which can be routed in various configurations by switch, depending on how many inputs you have at your disposal. Aural controls also reside here starting with the mandatory gain pot for each channel pairing. Crossover-wise on the satellite channels there’s a switchable low or high pass which can be set between 50Hz and 500Hz, while on the subwoofer channel there’s a 50Hz–250Hz low pass crossover, 10Hz–50Hz subsonic filter for ported applications, 0dB–12dB bass boost ability centred at 45Hz, in addition to the critical phase adjustment allowing 0° through to 180° (which is infinitely superior to 0° or 180°). Last but not least this end is also home to a remote input port, with the remote control and cable being supplied in the box.
Removing the bottom plate for an eyeball is a rewarding experience, as Focal has garnered quite the reputation for its mastery of amplifier design over the years. The FPX5.1200’s internal topology is wonderfully laid out upon a glistening blue PCB, and starts out with stiffening in the form of a quadruplet of 25V/2200uF caps. From there the power is shunted through a large air-core transformer for step-up, the newly raised voltage then being stored within six 50V/1500uF power capacitors, including a reserve for those occasions where a little more supporting current is required. Power is expelled courtesy of twin rows of highly efficient output transistors. 
Thermally speaking the layout sees the power input stage, power storage area, step-up transformers and output stage placed in thermally efficient locations, with the FETs literally clamped hard against the outer case to draw heat away from them. The power components are also kept well away from any signal handling, thus being less conducive to induced noise.
When the time comes to install the FPX5.1200, you quickly discover that given its diminutive proportions it fits in all matter of places you probably didn’t consider previously. I had mine jammed down within the confines of a side trim panel, vertically to allow cool air to flow along the heat sink. Focal also seeks to make your life easier by including clearly labelled instructions along with various tools and mounting hardware.
As always the auditioning process began long before the unit made it to the test car, with the first check upon the test-bench being that of the zero-noise track. The amplifier is not what you call completely hiss-free, but even at full tilt the hiss is minimal. Overall it’s one very quiet design, despite having plenty of power on tap, a real credit to the Focal designers. 
Getting to the car, I set up the unit with the oscilloscope before grabbing my music and heading out on the road. The delivery of sound proved most articulate, with the satellite channels remaining very clear and controlled even when pushed. Despite the fact they may not look as titanic as some on paper, rest assured there is still plenty of grunt, more than enough to aggrieve your ears. The subwoofer channel, likewise — its output is solid, defined and accurate, and all five channels display an impressive level of linearity combined with minimal distortion over their entire 10Hz to 20kHz bandwidth, even when pushed right to the brink. Naturally physics dictates that there is an upper limit; however if you feel the need to continually approach said point then perhaps look to the well-proven combination of Focal’s FPX1.1000 and FPX4.800 pairing instead.
Overall the FPX5.1200 is exactly what it’s purported to be — one very solid performer, offering a rich blend of overall tonality, control and precision. Focal goes to great pains to explain that if you’re looking to hit the lofty heights of 180dB… well then perhaps look elsewhere. But if you’re in the market for an amplifier that’ll vastly improve both the quality and volume of your listening experience, without consuming half your boot or bank 
account, well then, this is the unit for you.  
Focal FPX 5.1200 amplifier
Cost: $899
+ Well priced, well specified
+ Improved design
- SPL seekers may need to look elsewhere
Type: Class-D five-channel amplifier
Poweer: Continuous power rating 4 x 75W + 1 x 420W @ 4 ohm, 4 x 120W + 1 x 700W @ 2 ohm
Features: Adjustable crossovers, bass boost, phase control, input shunting & remote level controller