Hey guys, so yesturday I spent about 7 hours putting in a nice set of Hifonics components in my doors, and a set of 6x9's in the rear. That went pretty much seamless, but once again the subs are a problem. My brand new Kenwood Amp blew as soon as the volume went up. Then I hook up the crap amp I had as backup, and that only has 2v across it from power to ground. My ground connection is good, the fuse looks ok. All connections checked a hundred times. This is the part I HATE about doing installs. It's all too much of a pain in the ***. And mine never seems to work well.

So. I need either suggestions on how to fix this problem, or what a good amp would be to push two 10" subs that are rated for about 250-500w rms, and 4ohms. the subs are great, but they seem to kill amps. What do do...

 

kicker 08zx7501 750 watts rms enjoy

 

nah - get the Alpine PDX 1.1000 -- 1000 watts RMS, has the footprint of about a piece of paper, and produced almost NO heat.

 

alpine makes a great amp!

 

Are you running straight power from the batt. to the amp? If you had a fuse <2ft. from the batt. it would blow before the amp fuse will blow.Clicky

I think I have an 80amp fuse in the holder and have never blown out an amp...

 

Yea Ive never blown an amp either but Ive been through quite a few fuses lol.

Been running the same JL amp now for over 2 years.

 

What size power cable you running? Where are you picking your ground up from? Have you tried checking the voltage at all the places where wire is exposed (ground lug, each side of the fuse, connection to battery, etc?)

 

I am running 4g wire, the fuse is more than 2ft from the battery, and its not the amp fuse that blows, its the amp itself. I have the ground hooked up on a bolt under the mat in the trunk, never had a problem with it before. Haven't changed it, or played with it ever. I checked all connections, and everything is solid, the only reading I get that is out of place is when the amp is on, getting 2v from the battery input to ground. How much are the two amps mentioned before?

 

What is the total impedance of your subs (if they are each 4 ohms, the total load could be either 2 or 8 ohms depending on how you wire them) and are you running in bridged mode?

Many amps are only 4 ohm stable in bridged mode. Connecting a 2 ohm load in bridged mode can kill an amp.

Also, make sure your crossvers are set to low pass @ 60-70 hz. No higher, and turn off bass boost.

I run an arc audio amp. I didn't feel like screwing around with cheap stuff and it's designed to power a 5.1 setup, including a method of merging the left and right channels to make a front center. (One day, I'll have true dolby 5.1. Mark my words...)

If you're only getting 2v across your 12V rails.... I don't know what you did, but i suspect you had your multimeter set wrong, or you were using it incorrectly. Otherwise you have a high resistance load somewhere between the battery and your amp. I'd replace the fuse under the hood first. I've heard of them going bad before without the middle actually melting out. I'd think a bad connection would get you 12v but very little current...

 

Socket, all good advice, I will probably get some new fuses and hope that works. Yes, I have them bridged, they are 4ohm impedence subs, so bridged its a 2ohm setup. In truth, you may be right about being unstable at that load, but I had it hooked up that way for a few months in the summer, and as long as I kept it tuned low, it didnt seem like a big problem. But you may be right. It isnt easy finding good amp that puts out 800-1000watts, and stable for 2 ohms. I have been considering just getting different subs. It's all a money pit >

 

Wire them in series and get an 8 ohm load. Theoretically, it will be quieter, but I doubt that you'll notice, seeing as you'll be able to bring the gains up safely. My amp is 2 ohm stable in non bridged mode, and is running a 4 ohm sub. It's not even a high end sub, and it's overkill. with 2 10"s @8ohms bridged and a 1000 watt amp, you should be able to annoy the neighbors no problem.

The problem with a 2 ohm load in bridged mode is it forces the amp to pass more current then it's capable of handling through its circuits, and causes it to melt. It could be fine for years at low volume because the current never gets to high, and then the day you crank it it will blow up.

PS: I just looked up the RMS ratings for the sub channels on my amp. 155 watts, and my car is loud enough that you don't want to sit in it when the volume is all the way up. In bridged mode, it'd put out 500 watts at 4 ohms. It's also not 2 ohm stable in bridged mode, so I'd give up on finding an amp that is.

 

It's not the low impedance that usually kills an amp, it's high-current. Most 4 ohm stable amps will handle 2 ohms ok up to half volume. Past there and the current is too much for the amp. Wire the subs up 8 ohm and you'll probably get almost the same volume as 2 ohm, but you won't risk blowing your amp. There are plenty of amps that are 2 ohm stable bridged. They're usually high-power amps though. There are also mono amps out there, which are generally 2 ohm stable, and are available in fairly small powers.
I've heard good things about the Alpine PDX series amps lately. They're tiny, light and powerful. They're class D amps, so they're very efficient, but more susceptible to high harmonic distortion because of that. They're a good fit for subwoofers though. The mono PDX amps are only good up to about 200 Hz, so they're strictly for subs.
The model I'm looking at right now is the PDX-1.600. 600 Watts mono into 4 or 2 ohms (not sure how they manage that.) They're conservatively rated from what I've heard.

 

Lower impedance == higher current.

Halving the impedance should in theory double the amount of current that will flow. So impedance and current should not be thought of separately. You need to think of them as working together to blow up your amp. Yes, current is what fry's the amp, but it's the low impedance that lets that much current flow in the first place.

You don't need 2 ohm stable amps for sound quality. 4 or 8 ohms can sound just as good. Audio is an art as much as a science and while you can throw numbers around all day, a system that's been well tuned but has "worse" numbers will sound better then a poorly tuned system with "better" numbers. Just throwing this out there because people seem to get caught up on impedance's and getting "maximum power" out of an amp, when realistically, your system will never reach that kind of output the numbers say it will, and if it does, you wouldn't want to be inside the car when it is.

Forget about getting a 2 ohm setup to extract maximum power out of your amps, and focus on building a system that won't clip or distort, or let the blue smoke out of amps/speakers. Impedance are a good place to start to make sure bad stuff won't happen, and are not a good meter of how loud or how good the system will sound.

 

yeah it was ok up till about 17 or so on the factory radio volume ****. then it just popped. Do you think it can be fixed? Knowing what went wrong, I would do it better but I would like to ideally just get the amp repaired then buy a new one.

 

There may be a fuse inside the amp, but if it's not that, unless it's a really expensive amp it's probably not worth fixing. When I've killed amps in the past there's usually significant evidence of what went wrong (burned traces on the PCB, cracked transistors, etc.) If there are no problems with the board it might be possible, but I'd imagine the type of places that repair amps would be pricey.

 

i havent cracked it open to look...

 

If you're going to try and RMA it, I wouldn't open it. Include a really nice letter when you send it in to saying how you love their products and this is the first one you've ever had a problem with, and you're sure that the wonderful people at the amp factory can put everything right for you so you can continue to tell people to buy their brand.

Also include your receipt. They'll want that.

 

So I found this amp, and from the description it seems to fit exactly in my power needs, I know some people who say that if you pay less you get less, but RMS ratings are supposed to be illegal to fudge. And for the price it totally seems worthwhile. Free shipping too....

http://www.onlinecarstereo.com/CarAu...roductID=16487

 

Also, I did swap the speakers out, and the difference is astronomical. Apart from some plastics rattling in the back because the 6x9s pushing up on it a bit, its flawless sound. For anyone looking for speakers, Hifonics makes some awesome stuff. And the crossover that came with it its miint. With all my subwoofer woes, the speakers were the first ray of sunlight I've had. But I do notice that they are hungering for more and the radio just wont go loud enough to push them.

 

Like hell it is.

And if you're looking for a new sub amp, stick with a single-channel 2 ohm stable amp. I know you're not looking to spend a fortune, but you've been happy with Hifonics products already so:
http://cgi.ebay.com/HIFONICS-BRUTUS-...QQcmdZViewItem

 

thats not a bad setup, so I take it from your offering an alternative, that you dont suggest trying it out?

 

The Lanzar? **** no I don't suggest trying it out. They make crap. Always have and always will.

 

Ok so I cracked up in Kenwood amp, and am testing ohms for continuity. Enclosed in this post is a picture of the DMM for what it is set at, so you can help me understand what I am seeing (hopefully)
At 2000K resistance (wierd labeling for sensitivity, but w.e.)
From the Battery, to the ground, it said 35ohms, but also went up and up until it went to no connection
Across the bridge I have 80ohms, but it escalates, and wont sit still, going up until no connection

Now, I am thinking that my old mans DMM is crap, but that doesn't answer the q of what happened to the amp, and if it is fixable. I am going to get a bunch of fuses tommorow to replace the one under the hood which i suspect is faulty, causing massive resistance in the line.

If I take the DMM off of the amp for a while, it resets and gives me a reading, showing that the power and ground are indeed connected. Im so confused...

 

heres how i am hoping to get the trunk set up when i figure out the amp woes. I am planning on moving the battery out of the engine bay, and into the trunk. I am trying to open the engine bay up, so I want to make a relocate for the batt. (I don't want to hear anything from anyone about how it would adversely effect the cars performance, I am not interested in racing it, this is all for show. Also, for the amps I will build a false floor, with plexiglass to see into it. The amps sitting there are for fitment and design only. I may use the crunch to power my speakers tho... havent decided. And the crossover will be mounted to the back of the amp box. This was just a layout shot, to get an idea where things are going.

 

Where's the picture of the DMM? It sounds like you're using it wrong. The resistance setting on a multimeter can only be used on unpowered systems. Your power connections should be reading approx 0 ohms, if they're reading more than 1 ohm you've probably got a problem, or are doing something wrong. If the resistance reading is going up, it probably means that there is a cap or inductor in the system which the meter is charging, and it's screwing up the reading.