I installed the same amp in our XT over a year ago, and I have some good news: You can absolutely power it using the head unit's 12V power lead.

In general, I would not recommend this wiring method, but in this case it is perfectly acceptable. I'm an engineer and have installed this exact amp in three different vehicles; it is a phenomenal product for the money.

You're actually removing most of the load from the head unit and shifting it to the outboard amp, and the total combined current might even be less since the Alpine is going to be a more efficient amplifier. You're also protected with multiple fuses.

Now, if you really want to make the system come alive, buy the OEM Kicker speaker upgrades, add an underseat sub (I like the Kicker Hideaway), and set your Alpine high-pass crossovers to around 100 Hz using the dipswitches. Otherwise, you're just putting more/cleaner power to fairly lousy speakers.

Good luck!

 

I run the same amp with the same harness you're waiting on powered by the head unit without any problems. I have mine bridged to two channels and stashed in the dash and have not had any overheating problems in the Phoenix summer. I wouldn't bother connecting it directly to the battery. If you use the harness from SVXdc it's a really easy splice less install.


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Thanks very much both of you for the info very helpful, my main concern to using the factory head unit power with the new amp was the load on the car's audio unit circuit- the Alpine's manual says to use battery power if the audio fused power is less than 15 amps and according to my car's manual it's 10 amps in the under dash fuse panel. Maybe I'm misunderstanding this, but you guys haven't had any issues. I forgot to mention that I do have the Kicker speakers and tweeters upgrade already and want to hold off on the powered subwoofer until I hear what the powerpack upgrade sounds like. I see that the powerpack has an internal 15 amp fuse as well as an inline one on the yellow power lead so if the car's audio fuse rating is fine yes there's multiple fuse protection going on.

From the Alpine powerpack manual:

"6. Battery Lead (Yellow)
There are two options:
a. Connect battery lead to OEM radio fused circuit
The OEM radio circuit has a fuse to protect your
vehicle’s electrical system in case of a short circuit. Do
not connect the battery lead to the OEM radio circuit if
the fuse rating is less than 15A.
b. Connect battery lead directly to BATT +
Be sure to add a 15A fuse (sold separately) as close as
possible to the battery’s (+) terminal."

 

Additional info on audio fuses in my car attached. The fuse/relay box inside the cabin below the dash has a 10 amp audio fuse, the main fuse box inside the engine compartment has two audio fuses, 20 and 25 amp.

 

I've also run this amp off of the factory head units power circuit with no issues. It will be fine and is an excellent bang for the buck. Dave.

 

Don't believe 25A fuse applies to non-HK systems, but...

Additional info on audio fuses in my car attached. The fuse/relay box inside the cabin below the dash has a 10 amp audio fuse, the main fuse box inside the engine compartment has two audio fuses, 20 and 25 amp.

I believe the 25A fuse is for the OEM external amplifier that comes with the HK system.

I'll bet you $1 that either a) there's no fuse there, or b) if it is there, you can pull it and your stereo would still work.

Depending on how much is prewired, and where it terminates (not sure where the HK amp resides in the vehicle), that could be a great way to add an aftermarket sub later. I ran a dedicated lead through the firewall for mine, but didn't think to investigate if there was prewiring in place for the HK system, which I didn't opt for in our XT. If it's fused for 25A, that's way more than what would be needed for my Kicker Hideaway sub, which has a 15A fuse on the main feed, and a 10A fuse on the unit itself. Something to think about if you decide to add a sub later...

 

Thanks all for the info, it seems there shouldn't be an issue running the amp on a 10 amp circuit, but since the car is still under warranty I feel more comfortable powering the amp from the battery. Plus I want to follow Alpine's own recommendation. Now the waiting game continues (3 weeks) with the apparently swamped Mr. SVXdc for his harness I want to order....

 

Thanks all for the info, it seems there shouldn't be an issue running the amp on a 10 amp circuit, but since the car is still under warranty I feel more comfortable powering the amp from the battery. Plus I want to follow Alpine's own recommendation. Now the waiting game continues (3 weeks) with the apparently swamped Mr. SVXdc for his harness I want to order....

I feel like I was sooooooo lucky with SVXdc....He shipped my harness the same day I asked for it.......incredible

 

Check your PMs



Check your private messages regarding this please thanks!

 

So I got curious about the inline fuse on the Alpine amp's yellow output/power wire & thought I could pop off the little cover on one corner of the fuse housing to see what was inside (like a replaceable fuse)- the manual says nothing about the inline fuse- and it appears the unit is sealed but says 5 amp inside. The cover just broke off I guess i can dab some glue on it but does anyone familiar with the 445u know what the deal is with that type of inline fuse? It doesn't appear it's meant to be opened. I guess it could be some sort of fusible link meant to be replaced if it ever blew?
UPDATE: so I did further research and I guess it is a "power noise reducer" attached to the Alpine's yellow power wire: http://www.f150forum.com/f30/small-4-chan-amp-installed-96750/index25/

 

Hmm....that sucks. I'd expect Inline Fuses to be easily replaceable/accessible....weird

 

So I got curious about the inline fuse on the Alpine amp's yellow output/power wire & thought I could pop off the little cover on one corner of the fuse housing to see what was inside (like a replaceable fuse)- the manual says nothing about the inline fuse- and it appears the unit is sealed but says 5 amp inside. The cover just broke off I guess i can dab some glue on it but does anyone familiar with the 445u know what the deal is with that type of inline fuse? It doesn't appear it's meant to be opened. I guess it could be some sort of fusible link meant to be replaced if it ever blew?
UPDATE: so I did further research and I guess it is a "power noise reducer" attached to the Alpine's yellow power wire: Small 4-chan amp installed - Page 25 - Ford F150 Forum - Community of Ford Truck Fans

The following link is a very good review of this amp. The third paragraph describes the "choke" that you broke open, and it's function and the importance of leaving it in place:
http://www.amazon.com/review/R3ARA7...dp_title?ie=UTF8&ASIN=B003VVYL46&channel=detail-glance&nodeID=1077068&store=car

 

Thank you for the link, yes a very good review- I ran across it while researching the amp but didn't note the "choke" info. I wouldn't have removed it at any rate & will glue the little cover back on!

 

Okay so for any 2014+ owners out there who have installed this Alpine amp where did you put it? I pulled my OEM headunit unit out (CF625UM) thinking I had enough room to mount the amp to the head unit itself but there's actually no way I can fit it anywhere in the cavity where the head unit lives. I had found a slick install post on subaruoutback.org where the guy was able to mount the amp to the bottom rear of his factory headunit (2015 Outback) but obviously there's more room available in the Outback dash to do that. I can't find any alternate locations behind the dash where the amp will fit on its own, and want to stay clear of the passenger front airbag location. Also the glove box. So I guess under the driver's seat would be the closest location to the headunit? Finally got a harness from SVXdc so I'm itching to get this amp installed!

Update: Thanks to Athens Turbaru for some feedback about this I checked again and there is room for the amp and wiring behind the A/C controls under the head unit. I plan on mounting the amp vertically using velcro or double stick tape to the rear "wall" (heater box or ?) behind the head unit and A/C controls. It will be tight and not pretty but will make it a short run of wiring between car/amp/headunit while using the SVXdc harness. I'll post some pics when I install the amp.

 

Mine is just crammed in behind the lower cubby. It's been in there over a year and hasn't had any issues. I was a bit worried about the Phoenix summer but it never shut off so lack of airflow there isn't an issue.


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xJoe thanks. I'm in the process of mounting my powerpack with velcro & zip ties vertically back in there behind the little lower cubby too, towards the steering wheel side. It will be a birds nest of wires in there but I think there's enough room to fit everything & not have the amp totally smothered. But it apparently doesn't get very warm on its own thankfully.

Did you use the blue/white remote turn on lead supplied with the amp (on the input/headunit side), or did the amp turn on on its own (using its "Remote Sensing" function)? I'm using the speaker level inputs because I'm keeping the factory head unit- like I think you did.

I see you did some raammat/ensolite sound deadening in the doors, I'm thinking of doing something like that in the future- at least the two front doors for starters. Maybe I'll hit ya up for some advice down the road if you don't mind.

 

Help low hum in speakers after amp install

Need some help/ideas- I installed the amp behind the cubby space in the dash under the head unit but even with it crammed in as far it will go at the very bottom so there's space between it and the head unit (at least several inches) I'm getting a steady low hum in the speakers with key on or engine running/any source selected (am/fm/usb/etc) and at no or low volume (when it's obviously easier to hear the hum). I had the gains set between 8 to 9 o'clock. I ran the amp's ground wire, and a separate very short ground wire I ran from the head unit so both share a bolt I installed on a metal support piece next to the head unit. I tried to separate as best I could the end of the amp power wire (from the battery) and the speaker wires but since space is so tight in there it's difficult to gain much separation. I really don't want to live with this hum - music or loud talk radio will mask it but at low volumes of sports or talk radio it's there and is annoying. Pulling the head unit away from the dash or moving the wiring & amp around doesn't affect the loudness of the hum it stays the same. Also I have the amp set on speaker level input and left the female RCA connectors on the amp and added male RCA's on the head unit side of Svxdc's harness, for easier connections with an aftermarket head unit's RCAs if I ever go that route. UPDATE: the new rca plugs I added came attached on 8 inch long 16awg speaker wire- I wonder if I should have used shielded twisted wire rca plugs like a Rockford Fosgate type?

So especially you guys who have installed this amp back with the factory head unit did you have any issues like this? I'm not sure if this is some sort of electrical interference or a ground (loop) issue. Or if my power wire is causing issues during its run from the battery back to the dash thru a grommet in the firewall? Maybe it's normal for an amp to have some background hum heard thru the speakers? I've been dinking with this damn amp & pulling out the head unit too many times I'm losing enthusiasm for this project!! Appreciate any help thanks. :crying:

UPDATE: the power wire from the battery to the amp is 10 awg; just before the amp I connected it to the amp's own yellow power wire (with has a choke attached) and is 16 awg. The amp's own ground wire is 16 awg which runs about a foot to my ground bolt. I wonder if I should replace most of that 16 awg ground run with 10 awg wire to match the power wire? I always hear you should match power and ground sizes but wonder if it makes any difference with that short of a distance?

 

I didn't run power or ground for mine, I just tapped into the wires on the harness from svxdc to use the head unit power and ground. I don't remember if I connected the amp turn on wire, but if I did I just connected it to the harness wire svxdc recommended. I know I did run a turn on wire to the sub under the seat since it wouldn't consistently turn on. If I remember correctly I just went from speaker wire to male RCA for the input to the amp.

I just tuned by ear using some test tones i downloaded. I don't have a hum or any extra noise.


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Thanks for that info. Since nobody seems to have issues with their Foresters running that Alpine amp using the factory head unit power and ground heck I'm getting to the point of doing it too, as long as that hum disappears. I've never used any kind of external amp so just don't have the experience to know what to expect.

 

kōbai-iro... Mine had that humm - white noise if you will, could not notice once turned up. However, that was not going to work. I had the input switch wrong I presume and turned the gain almost all the way down.

Verify that you do not have it on RCA. Seems like it should be 4ch - Speaker on the inputs.

 

Flint, I have the amp input set to 4 channel (I have the 4 Kicker upgrade door speakers and 2 dash tweeters) and Speaker. Front and Rear HPF are off. Gain I moved between roughly 8 and 9 o'clock.
I want to be on speaker level input and just have the amp input wires connected with RCA plugs to keep that function for later use if needed.
I saw your install post btw. I don't have a sub. You said you were having a loud hiss originally but that seems it was due to having the amp settings wrong. So after you were all done and liked the sound you had no hiss or noise at low or no volume in the background? My sound is a definite steady humming tone not a hissing fwiw. The next chance I get I will zero the gain down and go up from there and see what it sounds like. I've had the dash apart and things in and out so many times I can do this blindfolded. I think I have a permanent case of carpal tunnel though on my hands.

 

Correct, with volume down it is perfectly silent on mine, no hum, hiss or whatever it was.

And yes, you can use the rca connections. I just cut them off.

In hindsight I would not suggest the amp behind the head unit. If you go back in, lengthen the lines so you can put it where you can get to it.

 

Yeah in a perfect world the amp would be away from the dash and more accessible but there are very limited places for it in these vehicles, besides glove box or under the driver seat which I don't want. I'm going to try to find another grounding point for the amp behind the dash or maybe in the shifter console area- if that and adjusting the gain doesn't remove the noise I will re-wire the amp to the head unit power and ground wires. At least my head unit doesn't have 14 connectors like yours omg! It's bad enough with the few it does have.

 

Update: a new grounding point didn't eliminate the hum so I rewired the amp to use the head unit power and ground wires but still have hum- no change at all. When I zeroed the gains the hum was still there and when the gains were increased past 9 or 10 oclock position the hum level stayed the same but then hiss increased. I tried the amp's RCA setting instead of speaker but no improvement and a little worse hiss. Seriously nobody else with the non-nav CF625UM head unit and the Alpine KTP-445U amp (no subwoofer etc) can hear a background hum noise at no or very low volume with any source (AM/FM/USB/CD)??
If this is expected with the crappy head units we get stock with the Premium level ok so be it, I would hope an aftermarket head unit would produce a cleaner signal using RCA outputs if that's what I have to do to get no humming!

 

Update: a new grounding point didn't eliminate the hum so I rewired the amp to use the head unit power and ground wires but still have hum- no change at all. When I zeroed the gains the hum was still there and when the gains were increased past 9 or 10 oclock position the hum level stayed the same but then hiss increased. I tried the amp's RCA setting instead of speaker but no improvement and a little worse hiss. Seriously nobody else with the non-nav CF625UM head unit and the Alpine KTP-445U amp (no subwoofer etc) can hear a background hum noise at no or very low volume with any source (AM/FM/USB/CD)??
If this is expected with the crappy head units we get stock with the Premium level ok so be it, I would hope an aftermarket head unit would produce a cleaner signal using RCA outputs if that's what I have to do to get no humming!

OK. I have the 2016 so not quite the same HU. I have a different amp, but can tell you the HU in mine only puts out very low white noise, or hiss. I can only hear it with the engine off, volume high and no music playing. In reality, it is a non issue because it will never be heard. This is probably the 'hiss' you describe. If it increases with the amp gain, it is likely coming from the HU. Can you live with this hiss? It will be there regardless of the amp you use, since it is in the source signal.

The hum you have isn't coming from the HU. If it does not increase with the amp gain, the it is not in the source signal (the HU). This hum is coming from your amp. I don't know how much noise is to be expected with that little Alpine amp (it isn't a very pricy or high quality amp).

Assuming the 'hiss' is acceptable and the 'hum' is not, I suggest a new amp. If even the 'hiss' is unacceptable, then you need a new HU.

It is also possible the hum from your amp is due to power wiring, but it sounds like you eliminated that. I would still recommend a new amp be placed under the seat or in the trunk and grounded to a chassis bolt, not placed behind the dash.

Background on me: I'm an electrical engineer and have installed amps, subs, speakers, etc, etc in three or four of my vehicles, always keeping the stock HU (for anti-theft reasons).

Hope this helps some. Good Luck.:smile2:

 

EJH, thank you that helps a lot! I assume you have the new 7" touchscreen head unit. Have no clue if that has cleaner output than mine. Anyway hiss isn't an issue as it was only noticeable when I tried switching the amp's input setting from speaker to RCA and cranking up the gains beyond 10 oclock. I tell you without that pesky hum I really enjoy the sound I'm getting. It's the hum that is my issue and as I said it's steady at no volume and low volumes of radio (volume level 1 to 3) where I really notice it. As you may or may not be aware there is a wild difference between volume levels on the head unit depending if the source is switched to radio or CD or AUX/USB (I listen to most of my music on a thumbdrive). Radio is LOUD at "10" when that setting for CD/USB is not at all. Anyway I could live with the hum if it wasn't for the many times when I'm listening to radio at low volume (especially when parked with engine off) and there's that annoying background humming. When I power on the head unit when the volume is turned way down and I can hear it there is a very short pause before the hum kicks in- obviously the amp's "remote sensing" function has detected the head unit sending power thru the speaker inputs to turn it on.

Yeah the original power wire to amp was directly from battery and then I powered the amp via the head unit power and I tried to be careful about keeping power and speaker wiring separated, as well as trying two different ground points besides the head unit's factory ground wire. Yes the Alpine amp isn't that pricey (around $100) and something like the Pioneer you have seems like a good step up. [Update] But there doesn't seem to be a direct replacement for it in Pioneer's line-up- just the 100 w/ch 8604 model. All things being equal I would prefer retaining the factory HU but just get a little more punch and quality sound. If the Alpine powerpack had worked out I was fine with the it, the head unit, and the Kicker upgraded speakers for sound. I don't need a subwoofer. Hey thanks again.

So the 4 Kicker upgrade speakers I have say "50 RMS" and "100 Watts Max" on them, so for those in the know what power rating should I look for when looking for an amp to properly & safely drive them? (and the two Kicker tweeters in the dash). This Pioneer looks good http://www.crutchfield.com/p_130GMD8604/Pioneer-GM-D8604.html?tp=115 but I don't want more amp than I need either.
Crutchfield recommends running new wire to speakers if using a "high power" amp (100+ watts/channel) which I don't want to do so I guess an amp in the 60-75 watts/ch range would be good for my Kicker speakers and oem head unit? Update: these amps looks promising and small footprint:http://www.crutchfield.com/S-RSJf4hthWym/p_023EMA455/Blaupunkt-EMA-455.html and http://www.crutchfield.com/p_109GXA604/JBL-GX-A604.html?tp=35782

Thanks

 

Help please. Latest troubleshooting for the steady hum I'm hearing in speakers- I unplugged all the rca plugs on the input side of the amp (coming from the factory head unit) and the hum disappears. Of course the amp auto detects a signal from the head unit to turn on so I don't think unplugging the rca inputs determines anything like if the amp or head unit is causing the hum but what the hey. I have the head unit and amp and most of the wiring as far away from the dash as possible to minimize any interference issues. There was no hum until I added the amp but I can't figure out how to narrow it down to the amp itself or a noisy signal from the head unit being amplified. It is a speaker level connection which can be noisier than a low level rca one I realize that. Frustrating because I seem to be the only one with this hum who has a factory head unit/speaker level/Alpine power pack amp combo...:crying: I'd hate to get another better amp and find out that one is just doing the same thing and amplifying a crappy signal from my factory head unit. I'd prefer to keep the factory head unit if I can... Anyway if anyone has any further troubleshooting advice I'd sure appreciate it!