Arc Audio KS300.4 vs Pdx F6

Hey guys,

Quick question- Im looking to swap out the old clarion and am trying to decide between these two amps. Speakers are Bullet 650 coax in an 03 SAN. Bow speakers will be ran off of front channels with the other two interiors. The most rear will be run off of the back channels.

I have no direct experience with Alpine or Arc amps, but based on my research, these are what I have narrowed it down to due to space, $ constraints.

Any thoughts?

I really like PDX amps they are super effecient, small, produce very little heat and pack a punch but the only thing that kinda stinks about them is that when you do run them at 2 ohms you don't see a jump in power. In this instance it looks like you'd be running 75 watts to the bow and front cabins and 150 to the aft. The Arc is a very nice unit as well and does allow for a bump in power when you run it at 2 0hms so you'd be 87.5 to the bow and front and 90 to the rears. The Bullets you are looking at have an RMS of 100 so you may consider something like the Exile xi 800.4 if you have a little more space (16x10) this will get you to your 100 watts rms on the fronts and bow and 125 to the rears so you'll have a little headroom. Just a thought.

That was my first choice since im running Exile for the tower, but that damn amp is a few inches too long! Id have to pull my whole mounting board and redo too much. I agree though, Id like to have as much headroom as possible. thanks!

based on my experience with the KS300.2, I'd have no hesitation in running a KS300.4.

Here is how it would normally play out.
Alpine amplifier.
The Alpine is 4x150 watts at either 4 or 2 ohm. Its fair to assume that all speakers would be gained the same for the same output level throughout the boat. So two speakers would be paralleled off each of two channels resulting in the division of 150 watts for 75 watts per speaker. Since the remaining speakers would be gained the same the power would still be 75 watts per speaker. So we are effectively driving 6x75 watts. What some may not realize is that if the amplifier is regulated to deliver the same power into both 2 and 4 ohms then it accomplishes this by cutting back on the power supply voltage at lower output loads. So in a four-channel regulated amplifier with a single power supply two channels with the lowest load automatically bias the alternate channels running at the higher load which would then be less power than the rating.
Advantages: The output section always operates in its optimum range and operates cleaner than other amplifiers do at lower impedances. It also maintains better efficiency at lower impedance loads.
Disadvantages: A loss of some potential power when used in asymmetrical applications. But this is not a disadvantage in this particular application because we want equal power to all six speakers.
Arc Audio amplifier.
As an unregulated amplifier the 2-ohm load will increase to 175 watts per channel divided by two speakers per channel so 87.5 per speaker. The other two channels which can deliver 90 watts into a 4-ohm load will be gained down to 87.5 watts so that the output levels on all speakers match. So we are effectively driving 6x87.5 watts.
Advantages: Being unregulated it does produce a premium of power at 2-ohms but that could be looked at as a disadantage where it loses power at 4-ohms.
Disadvantages: At a lower operating load you will sacrifice distortion, efficiency, damping and dynamic headroom. More continuous power at more compression.
Comparison: You couldn't possible hear a difference with 17 percent more power (from 75 watts per speaker to 87.5 watts per speaker). It would take an increase of 33 percent more power to produce a 1 dB increase which is the smallest increment you can discern in a perfectly quiet environment. Forget about it with a 5 mph hour wind.
Both the Class D Alpine and Class G/H Arc Audio are inherently more efficient than most amplifiers. Something that is definitely important.
I'd be happy with either.
Here is another option in or near the same budget range.
The highly efficient Class D JL Audio XD600/6 will deliver 6x75 watts into a 4-ohm load. With a dedicated channel per speaker and operating so conservatively you will have lots of extra headroom. Distortion, efficiency and damping are all optimized. You have three pair of gains for perfect level matching throughout the boat. You can add a level control to just the bow and make that a retreat area when needed.

David
Earmark Marine

Go with the Arc 300.4 I speak from experience as I have almost the same set up I am ruining four bullet 650hp coax and two bullet 770hp coax for interior speakers powered by an arc 300.4 and the sound is amazing loud clear and lots of mid bass.I just got back from the centurion gathering at banks lake.One of the members liked the sound of the bullets powered by the arc 300.4 so much he immediately called Dave and asked to buy some of the bullets but Dave said they were not available.

d_rock,

Anytime you can give each speaker it's own amp channel you're better off IMO. Go for a 6 channel amp.

I'm running a 300.4 for my (4) 6.5" in boat speakers, a 300.4 bridged for my two Pro80s and a 500.1 for my sub. These amps really make these speakers sing!

I went with the arc audio. Ryan at chucktronics hooked it up. Thanks for all of the feedback everyone.