Alpine KTP-445U Amp install
I thought I would post my experience with this relatively new product that I installed it in my 2007 S model. Sorry I don't have pics, but there really isn't anything to show that hasn't been shown many times on this forum already! You just need knowledge of the x9331 connector, the fuse panel, and how to get to each. That info is well documented in this forum.
First of all, this amp is a new version of an amp that Alpine has made for a while now. The original (KTP-445) was made specifically for Alpine Head Unit owners to add more power to their system and was an easy 'plug and play' install. The new version is a universal unit that allows install to any head unit, but still is MUCH easier to install than a regular amplifier. The ease of install is mainly because it is very small and can be tucked under the dash easily. Also, because it is a Class D Amp, it is incredibly efficient and requires little power so you do not have to run a power lead to the battery, it will run just fine off of the radio power circuit! It adds 45W per channel RMS to all four channels. THAT IS ABOUT TRIPLE THE OUTPUT OF THE BASE HEAD UNIT!
Second, let me fill you in on my system so far. It is a NON HARMON KARDON base model stereo. THIS INFO MAY NOT APPLY IF YOU HAVE A HARMON KARDON SYSTEM. I have Focal IS 165 components in the front. They are Focal's easy to install 'Integration Series' speakers and their entry level product. They are about $300. In the back I installed some Polk Audio 6x9's, around $120 or so... I also put in 'Peal N' Seal' for some Audio dampening and have found it to work quite well. The only other thing I have done is the 'Chanel Swap' that is well documented on this website. Thank you to all those who posted the wealth of info on changing speakers, Channel Swapping, and more on this forum!
Now for the amp... It will take line level and speaker level input, but as many of you know the easiest way to do this is to tap into the speaker level signal at the x9331 connector by cutting the leads to and from the harness and running them to and from the amp. When wiring the amp, keep in mind that the factory head unit does not send frequencies under 100Hz to the rear speakers, so many on this forum have performed the CHANNEL SWAP, if you don't know what this is do a search on here and you will be enlightened! Basically I flopped the front and rear output of my amp to keep the channel swap intact. I must make sure for those who haven't done their homework to NOT CUT ANY OF THE WIRES THAT ARENT SPEAKER WIRES! There are I think four wires that will stay connected to the x9331 connectors. I think they are a large brown, 2 small browns, and a white... Do a search on here for x9331 connector and you will see where it is and see many diagrams on the wire colors. This install is easy compared to installing many amps, but it does take some common sense, and maybe a little background in car electronics. ALSO, I must stress, DO NOT CUT THE LEADS IF YOUR MINI IS STILL UNDER WARRANTY! My car is WAY out of warranty and I was comfortable with cutting into those wires the way I did because I know that I can always go back and fix them later. You can also 'piggyback' the leads using taps but I chose to cut them from the harness and solder the leads together for a better connection.
After tapping into all of the speaker inputs and outputs, I ran a ground to a nut just below the bonnet release latch. Any good bare metal spot will suffice for ground. Next, the power wire was run along the firewall through the back of the center console, and behind the top of the carpet over to the fuse panel on the passenger side. I purchased a "add-a-circuit- fuse holder form the parts store (Autozone, etc) for about $7. You will also need about 4 feet of wire ( I think it is 12 guage) to extend the amp's power lead. I crimped the extended power lead onto the "add-a-circuit" power lead. I then pulled the Radio Fuse, put the "add-a-circuit" in the radio spot and put the fuse into the "add-a-circuit". The amp is just secured up under the dash with zip ties. BE SURE NOT TO OBTRUCT THE BRAKE PEDAL, OR ANYTHING ELSE THAT WOULD AFFECT CONTROL OF THE CAR! Also, no need to worry about the amp heating up, class D circuitry runs very cool, and will not be a problem with ventilation.
The setup of the amp is easy, there are dip switches on the amp that tell it speaker or line level, in this case we want speaker level. There are also High pass and low pass filters on the amp, I bypassed all of the filters for now and it is running full range. If I get a little powered sub for the back, I will change it to cut the bass under 100Hz. I also had to turn down the input gain to the amp some. Default setting was at halfway, I turned it down to about 1/3 of the way.
This amp REALLY SOUNDS GOOD! Especially for the money. Before my system was harsh sounding because there wasn't enough power to control the speakers. Now the system is very musical and has dynamics. Some people may poo poo this little amp because it isn't some high end amp for competition. For most people that love music but don't want to make heavy mods you your car, at the very least do the channel swap, put new speakers in the front's and buy this little amp. Putting speaker in the rear helps, but considering the amount of work involved I would say do that last.
Next I need a powered sub, I am looking at the Sound Ordinance Powered sub mentioned on this forum. It looks like an easy install as well!