AlpineKTP - 445 4–Channel Amplifier

Très heureux de mon achat, installé sur ma moto Kawasaki 1700 voyageur 2016, bonne emplacement pour l'installé et super le son...j'avais déjà changer mes haut parleurs 45 watts RMS mais ils ne sont pas assez puissants donc prochaine achat de nouveaux haut parleurs éventuellement, pour l'instant ça me convient parfaitement.

Let me first say that I currently own a car that has a aftermarket system in it that consist of one 12" JL subs running off a alpine monoblock pdx amp @ 2ohms/800 watt RMS, components up front and 6x9's in the rear running off a 4 channel 550 watt pdx alpine amp and it rocks hard. So with that said I know car audio and have been building out system for over 20years. Well I bought a 2014 ram 1500 Quad cab 5.7 HEMI 4x4 big horn edition with the 8.4 radio with the stock speakers. Wasn't a bad stereo system for the average person to listen to, but like most factory stereos it lack quality sound due to poor speakers and a crappy head unit(radio/deck). Well like most new vehicles, the 8.4 radio in this truck is tied to several features like the heating and cooling controls, navigation, backup camera, sat readio, settings for the truck, and several other feature as well. So replacing the head unit is not really an option I'd like to explore with this new truck. So I started to look around for a small foot print amp that didn't require running a power line with inline fuse from the battery to the amp and that could be placed somewhere behind the dash. I came across a few brands like clarion, fosgate, some off name brands, and this alpine unit, KTP-445U. Already having alpine amps in my other car, I knew I couldn't go wrong with it, so I made the purchase. Along with the amp I figured I'd order speakers to go with it. I decided on the Kicker-41KSC354 3 1/2 for the dash, Kicker-40CS654 6.5in for the front doors, and the Kicker-41KSC694 6x9's for the rear doors. The installation of the amp was simple and straight forward. Seeing how factory radios don't have RCA outputs, this amp allows you to cut the ends of the RCA inputs off each channel (it's a four channel amp) and use the lines for direct connect to the factory radio harness speaker lines. This also eliminated the need for a remote wire to turn the amp on because the amp detects the connection of the speaker lines and automatically turns the amp on when there is a signal coming over the speaker wire from the head unit. The best part was that this amp fit perfectly behind the factory radio and I was able to mount it to a cross support that was behind the radio. After installing the amp I next did the speakers throughout the truck. Another pretty simple straight forward thing to do. After everything was completed and put back, I reconnected the battery and fired it up and all I can say is fricking WOW!!! This little thing sure packs a punch. It turned this weak head unit/stereo system into something enjoyable. It's not a competition stereo, but boy was I shocked at how good it sounded. No engine noise of any kind! even with the headlights on. The gains are only turned up 25% of the way and it's running full range. For the cost of this amp and the ease of installation this thing is a winner. It will turn any boring head unit into a monster of sound. I should mention that this alpine amp will work with any factory head unit and most speaker configuration. If your vehicle has an upgraded factory system that already has an amp you will need to check out how many channels your factory amp is using and how many speakers your car has. My dodge has six speakers but the front dash speakers and front door speakers are tied together by the factory so they share the two front channels coming off of the amp while the rear uses the other two channels. So for any of you out there looking to do a inexpensive upgrade to your factory radio for better sound, this is your best bet. Are there other options or bigger amps you can install, why yes, but it's at a cost that most people don't want to spend. This little amp will please.

Die bisherigen Bewertungen haben mich hoffen lassen und ich wurde nicht enttäuscht. Der Anschluss war denkbar einfach und hat auf Anhieb funktioniert, hängt jetzt im Handschuhfach. Von dem Klang bin ich hellauf begeistert. Die Bässe erreichen gefühlt tiefere Frequenzen, sind wesentlich sauberer und überschlagen sich zudem erst bei höheren Lautstärken als ohne. Die Höhen sind klarer und kraftvoller.Eben ein Verstärker xD Der seine Wirkung aber nicht verfehlt.

It's made a noticeable improvement to the factory stereo in my Mazda CX 5. Where I was cranking the volume all the way up to 50, now I'm getting as much power at 30 with added clarity.It was easy to install, was able to find colour codes for speaker wires online and use a multimeter probe to find the accessory lead and make the connections.Small enough to jam in against the firewall behind the stereo.Can tap into ground and power leads for systems protected by a 15 amp fuse, so no running wires to the battery.

So let's start with what this is NOT.It is NOT a "big power" amp that is going to rattle your windows and piss off the neighbors. Nope. It's a small, Class "D" amp that roughly doubles to triples the power output of your existing head unit. To really take advantage of it you need RCA outputs from the head, although it will work with speaker-level outputs. This means that with a FACTORY head unit you will get much less than this amp can offer.Let me explain -- an amplifier can only amplify what you feed it! If you feed it trash you get louder trash. Your head unit's amp is only so-so to start with (yes, even the expensive aftermarket ones because they figure if you care you'll use the preamp outputs instead!) so you're inherently limited. As a result if you want good sound quality you need RCA (pre-amp) outputs from whatever you're going to connect this to, and you also need to use decent-quality cables (don't waste your money on things like "monster" cables, but do get ones with 100% foil+braid shielding - you can tell they're reasonable in quality because they've got some thickness to them.)Now let's talk about the amp itself. It's a Class "D" amp. A Class "D" amp is EXTREMELY efficient because the transistors in it are either "on" or "off." They thus dissipate very little power as heat. That's good. However, the way they work is by switching the power at extremely high speeds (typically at least 10x the maximum 20khz audible sound frequency) and then using a low-pass filter made up of reactive components to smooth the output. Due to the way these amplifiers work energy is reflected back up into the power supply as a natural part of their operation. You'll note that on the yellow (power) for this amp there is a black box with something inside it. That "something" is a choke (you can see the coil inside the box if you look carefully through the slot) and it is really important that you NOT cut it off! If you do there is a risk that some of the high-frequency energy the power supply generates inside the amp could be reflected back up into the car's power system. This is unlikely to make the car malfunction but you could easily wind up hearing it in the stereo's sound as it has a decent shot at making it into your head unit and if it does, it could color the sound (quite badly, in fact, especially in the high frequencies.) So in short don't cut that black box off the power wire in an attempt to shorten it up!The (relatively) small size means you should be able to mount this amp under the dash or in another convenient place, and it's lack of heat generation means it won't overheat and cause trouble in that regard. It requires a 15A circuit (the fuse in it is a 15A one) so some care is required in terms of getting power to it, and of course a SOLID ground is necessary.There is a set of DIP switches on the back side that set high-pass filtration if you want it (if you're routing low frequencies to a sub this may be helpful, although most head units have a decent high-pass filter in them as well) as well as whether you are using speaker-level or the RCA-level inputs. Again, I STRONGLY recommend against using speaker-level if you can avoid it.As for sound level this amp will roughly add 3db over what a non-amplified head unit will produce. It's maximum power draw is 180 watts before the fuse blows, and it's rated 45W/ch -- while it can drive either 2 or 4 ohm loads there is no boost to output driving a 2ohm load as there is with some other amplifiers. It's not going to be a lot louder (doubling perceived sound level requires a 10db change -- and 10x the power!) but it will be somewhat louder and, more-importantly, MUCH cleaner audibly.Make sure you correctly set the input attenuation by the input plug. If you have a 4 or 5V RCA output head unit you will need to turn those pots down quite a bit; if they're turned up too far you will raise the noise floor (and be able to hear it in the form of hiss) along with rendering a large part of your volume control on your head unit worthless since you'll run out of power in the amp first. The best way to set these is with an oscilloscope to be able to "see" the clipping, but few people do that -- as a guideline if you have a 4 or 5V output head unit (most modern units are either 4 or 5v in an attempt to get better noise immunity) having the input settings somewhere between 9 and 10 o-clock is probably about right. If you have low-level RCA outputs you will need to raise the setting commensurately.Properly installed and set up this little amp is awesome for what it is. Just understand what it is and what you are and are not buying. It isn't a beast, but rather provides a nice but modest boost and a very material cleaning-up of sound quality without having to deal with everything that goes into mounting and dealing with the cooling and power requirements for a "traditional" Class AB car power amplifier.For a bit over $100 that's pretty darn good.