Mobile Electronics Australia

There’s no shortage of choice for your dollars when it comes to buying a suitable 4-channel amplifier these days. In fact, I’d say that if you’re spending up to $500 there’s no amplifier category that offers more variety and performance for the money. So, competition is fierce then. Many brands choose to offer as much power as possible, and there’s certainly merit in this if getting loud is your priority. Yet Polk’s PA200.4 takes a different path, using some cool installation and display features as its highlights as opposed to using brute force. So before we right the PA200.4 off for bring a proverbial knife to a gun fight, let’s take the time to give it a thorough once over and see what other artillery it’s packing.

Okay, so, 35WRMS x 4 doesn’t sound like very much fire power, especially when source unit manufacturers are boasting as much as 20WRMS x 4 from their internal amplifiers. Time to clarify a few things. First of all, any power rating you’ll see on any device will come under a set of conditions under which it is claimed. These conditions may include aspects like frequency, input voltage, impedance load and – importantly - total harmonic distortion (THD). This latter spec is one of the most misunderstood on car audio. THD is not a fixed attribute that an amplifier has, and you most certainly cannot compare one amplifier to another using THD. Oh no.

THD is what amplifier manufacturers use as a threshold against which a power output can be determined. Typically the more power an amplifier makes when it is close to its threshold the higher the THD will become. So, for example, an amplifier may make 50WRMS x 4 when there’s 0.08% THD evident in its waveform, but if pushed to a point where THD reach 1% it may make significantly more power. Note that 1% THD is quite acceptable, while at sub bass frequencies most people won’t complain when as much as 10%THD is evident in the music signal. No, really.

Anyway, how is this pertinent to the modest rated power of Polk’s PA200.4? Well, the specs show that at 35WRMS x 4 this amplifier is only producing a paltry 0.08% THD, and therefore I would expect somewhat more from this amplifier under normal operating conditions where more THD is evident in the music signal. Checking the fine print in the owner’s manual reveals that a CE approved measurement of 45WRMS x 4 at 4ohms with 1% THD is provided. That’s much more like you’ll expect during day to day listening.

Now 10WRMS may not sound like much, but since we’re talking in addition to 35WRMS it is an audible increase. This is comfortably more than double (probably triple) what you could expect from a source unit’s internal amplifier at the same level of distortion, and therefore the PA200.4 is indeed a worthy power upgrade from stock.

The PA200.4 can also have either pair of its channels bridged into a minimum of a 4ohm load, with 100WRMS x 2 the resultant power output. Take my advice, though, and leave the PA200.4 to power full range speakers, as bass duties are better served by something with more grunt - like one of Polk’s mono models perhaps? They have three versions available with between 400 and 1200WRMS and priced between $539 and $1089RRP.

Features & Specifications

So if power isn’t its priority, what makes the PA200.4 worthy of consideration? I think it’s the presentation personally. This thing looks cool. Actually, to be more accurate, its cover plate looks cool. You see the PA200.4 is actually two chassis is one. That smooth, flat, sexy looking chassis you see is actually bolted down onto another full aluminium extruded heat sink. In fact, you don’t even need to use the cover plate if you don’t want to, or need a more compact size. But why would you leave it off when the cover looks soooooo much better.

Four small Phillips head screws secure the cover plate in place, and when done you get the ‘polkaudio’ logo and ‘PA200.4’ lit up in deep blue from behind. Sweeeeet. The cover panel also serves to neaten up the wires at both ends. In fact, you can’t get to the main power and speaker terminals without removing the cover plate – which makes under seat mounting a bit of a bitch to be honest. Hmmm…. Anyhow, if you so choose you can also remove the smaller end plates that screw to the main centre cover panel. These attach with four screws from underneath.

The whole cover panel can also be swapped around 180-degrees, which means you can arrange to wiring and switches underneath to suit the installation while keeping the illuminated logos pointed the way you need them.

One end of the chassis houses the power, earth, trigger and speaker output terminals. Here you just get run of the mill silver screw down style connectors. No gold, no insert, no grub screws, but it is easy to use and – frankly – other than being a bit of a pain for larger power and earth cables it works just fine. I do think nicer insert terminals are merited at this price point though please Polk.

All the action happens at the opposite end, where you get the four RCA inputs as well as a pair of pass through outputs. These are teamed with a small INPUT MODE switch that allows all four channels to operate from just the front pair of inputs. Combine this with the pass through outputs and a second PA mono amplifier and that means you can drive an entire system from a source with only one pair of RCA output. All PA series mono amplifiers include dash mountable remote level controllers too – so you have full control. Excellent!

The remaining controls are for the input sensitivity (allowing between 250mV and 7.5VRMS), the crossovers filtering, and the bass boost. The crossovers are quite basic, allowing full range, high pass or low pass for each pair of channels. Polk, though, don’t mention the cut off frequency anywhere in the owner’s manual or their website – though they do note the slopes are 12dB per octave. My ears tell me that it’s around 80Hz, which is perfect for 99% of installations. The bass boost is either +8dB at 40Hz or off. Given the lowish power output I’d leave the bass boost alone.

The final feature is a curious one. There’s a small female plug in the end of the chassis marked ‘LED/FAN’. A small male plug with flying leads connects to this, allowing you to connect external LEDs and/or a small thermo fan, and these are switched on and off with the amplifier. This could be utilized in a custom installation which is kind of neat.

With the bottom plate removed we can see that the PA200.4 enjoys a very neat and orderly circuit board design. It isn’t necessarily trying to be highly space efficient, though one secondary PCB does assist somewhat. Polk have spent up a little more on the quality of the main PCB compared to other affordable rivals – especially given the power output which doesn’t necessitate the double sided PCB. Nothing wrong with being a bit overbuilt though and this stands well for longevity. All in all its good quality work.

This showed out when I fired the PA200.4 up for a listening session. Yep, it sounded great, which is to say it sounds the same as every other amplifier that isn’t clipping. There are no strange noises when powering up, though I did hear a very faint ‘swoot’ sound through the test speakers on power down. You probably won’t hear this in a car environment it’s that quiet.

Conclusion

If you’re the type of listener who uses realistic (as opposed to ballistic) output levels then the PA200.4’s 35-45WRMS per channel is probably ample for you. Why you’d choose this amplifier over others is due to its trick appearance more than anything else. I also dig the flexibility of the RCA inputs for anyone who has a basic source with just one pair of outputs. Just make sure you’re chosen speakers can handle bass output down to at least 80Hz.