Question for one of our car audio guys.

[TrailChaser]

I've got a Kenwood amp from a friend and it works good till it blows out the 15amp fuse in the amp. I've noticed that it's blowing it out faster and faster evry time I have to replace it...(replaced it 4 times so far)

 

Does anyone know what could be causing that fuse to blow out? I know it's gotto be getting overloaded or shorting out, but it actually works good and basses good for a day or two. Then the bass just stops in the middle of a song. I'll get specifics on the speaker and amp and post those up in a minute or two.

 

Thanks for any help.

[TrailChaser]

The amp is a kenwood KAC-526

 

The speaker is a Rockford Fosgate 8" in a little box for a pickup truck.

[TrailChaser]

Here is an ebay auction for the exact same one... I could just get a new one from that guy... $15 probly no shipping because it's local and I could pick it up.

 

[packie88]

whats hte watt rating on the amp and whats the peak power on the subs as well.. to run subs u should have a mono class D amp. is that the correct fuse that should go with the amp. cause i know my alpine has two twenty amp fuses for 700 watts. and my previous 310 watt mtx had a single 35amp fuse.

[89_trailboss]

you dont need a mono amp to run subs. most of them are made to only run a sub. but it is said that you get more "control" if you bridge a 2 chanel A/B amp.

 

You may be running the amp too hard. turn the gains down and see how long it goes for.

[Electrifyliak]

I'm with packie, my 300watt amp has a 25amp fuse if I recall correctly. 15 doesn't sound like enough for a car amp to me. Also, are you sure your wiring is all correct? That looks like a 2 channel amp, so I'm assuming you're bridging it. Are you bridging it correctly (negative from one channel and positive on the other)? I would probably double check all the wiring, make sure nothings crossed or grounding out on the sub itself or the amp. If it still blows, get a bigger fuse, and if nothing melts, you might be good. If the bigger fuse blows, you might just have a bad amp or something.

[packie88]

actuallt running two subs of a mono class D amp is no problem

 

 

you have,

 

 

 

Pos(+)_______(+)________:

amp sub :

Neg(-)________(-) :

: :

: :

___: :

: :

: (-)sub(+)___:

 

 

 

srry if my diagram is bad.(im not really good at this line dot crap to explain stuff.) but pretty much running a mono class D amp on two subs is no problem and in my mind i would reccomend it much more then a 2 channel amp. I had a 2 channel on my subs and it sounded good. i switched over to my mono class D amp and it sounds so much better, crisper and louder . running a 2 channel amp is jsut easier to wire. + to + and - to -. on one sub to terminal. mono class D arent hard at all. and in my mind better for the subs. The class D amps are ment for subs. so im with Electrifyliak check your wiring to the amp and then if you think thats okay check your wiring from your amp to your subs.

[packie88]

if you need a wire diagram hit me up on aim at packie88

 

or email packie88@comcast.net

 

 

casue my diagram did not work and turned out really bad.

[dnodog]

I think you need a bigger fuse, most high output amplifiers use at least a 25amp fuse, Turn down the gains and recheck your ground.

[TrailChaser]

I think it's a 200watt amp. I don't have it bridged, because I don't really know how. I don't know what watt the woofer can handle, because I bought it at EZ Pawn for $40 and haven't takin it out of the box to look at the back. The fuse holder on the amp says "15amp" but I threw a 25 amp fuse in there yesterday and went to the beach and ran it all day without any problems.

 

How exactly do I bridge the amp? What are the benefits to bridging it?

I have it hooked up by running a big (+) wire from the battery to the amp with a 30amp fuse at the battery. I grounded it to the metal body right next to the amp. I have the amp hooked up to the pioneer cd player via the RCA jacks in the back of the CD player to the RCA jacks on the amp. Can I still bridge it even tho it hooked up like that?

 

Does it really matter if you don't have the (+/-) speaker wires from the amp to the speakers right?

 

I DO have the stock amps bypassed FYI.

[dnodog]

bridge = more power(yeah)

sounds better if speakers are wire right{ in Phase} also some amps have one way circuitry so tends to cut out if speakers out of phase.

If the box says 15 amp use 15 amp... better to blow fuse than burn car, fuse much cheeper!!

[SC88Pathy]

Bridging an amp just refers to putting the pos and neg wires for the sub in the furthest terminals, instead of being right next to each other they should be seperated by two terminals.

[QuismO]

Bridging an amp just refers to putting the pos and neg wires for the sub in the furthest terminals, instead of being right next to each other they should be seperated by two terminals.

sc88's right. however, some amps have the terminals situated differently. sc88's explanation works if the speaker output terminals are pos, neg, pos, neg. (you can still bridge it this way using sc88's explanation if you invert one of the channels) but i believe yours is L+, L-, R-, R+. To bridge your amp...connect the positive speaker wire to your L+ terminal on your amp, and the negative speaker wire to the R- terminal on your amp...thus using the power of both channels, but bridging them into one channel. a 15 ampere fuse is possible for the older low wattage amps, and it should suffice for your amp.

 

try this bridge with the 15 amp fuse. DNODOG is right, better to blow the fuse than your amp or in a freak accident, a car fire. chances are, if you have a two channel amp trying to power two channels, but only have one channel hooked up, that one channel could possibly be drawing too much current, thus blowing that 15 ampere fuse.

 

 

A

M

P L(+).....to speaker Positive terminal

L L(-)

I

F R(-).....to speaker negative terminal

I R(+)

E

R

 

 

you don't have to do anything on the other side of your amp, in terms of ground, positive wire hookup, and rca cables to your deck. hope this helps...let us know how it goes

[*Night_Ryda*]

I'm looking at my old KAC 744 (only a model up from yours I believe) as I type this, and its using a 20amp fuse, I've run it in all sorts of configurations with a variety of subs and never once had a problem. I wouldn’t recommend going to a 25 amp, and especially not a 30 you’re more likely to fry your amp before the fuse blows that way.

[lowrider]

The wattage of an amplifier obivously has a direct correlation to the amount of current it draws, the power drawn is proportional to signal amplitude on an exponential curve. If you take the bottom of the case off, you should be able to read right on the circuit board the fuse size it needs. It'll be stamped with '15A' or something like that depending on the size. The recommended fusing size of car audio amps generally follow a 1.45:1 ratio. Therefore, a 100W amp, the maximum current it will draw is 14.5A. Since there is no such thing as a 14.5A fuse, it'll have a 15A fuse, so on and so forth as the wattage increases, the current draw follows the same scale. In that example, the current draw is measured BEFORE the amplifier starts to clip. A bridged load on a A/B amplifier will clip at a lower volume than a stereo load on the same amp or a <2 ohm load on a true 'D' path amp, bridging a class A/B amp to a 4 ohm split load (the amp will see 2 ohms) creates undue heat, which the amplifier loses by clipping and distorting, and in turn, draws more current to run (think about how hard your truck works up a hill on a hot day) and will thereby pop a fuse. When the amplifier is 'resting' or turned on but no volume is present, it should not draw more than 1A. Measure that with a multimeter.

Also, it never hurts to overwire. Remember how long the run of wire is from your battery ALL the way to the back where your amp is. If you're running 10AGU, rip it out and put 8AGU in, or preferably, if you can afford it, too, do a single run of 4AGU, then you'll be set if you ever upgrade or add a 4 channel to run your speakers.

 

Hope this helps.

Edited December 14, 2005 by lowrider

[Guest 05thumpinpathy]

just turn down your gain and bass levels your putting to much to the subs and the sub is in turn "popping the breaker"just like in a house when a breaker is switched off the subs can only withstand so much before seizing up...turn all your controls on the amp down turn all your bass from your deck down put it to your highest listening level and control your bass from your amp...when you reach this level you should be fine...if not get an amp that will not overpower your sub but just be right below your rms on your subs you dont wanna max out your subs you wanna let them move distortion free... also make sure your running the right size box and that your ground is hooked up directly to your chasis not an upright or support bar on your car...something that wont spike when something that is also grounded to that portion of your vehicle is used say a light or window...make sure your ground wire is also big enough to withstand your "load" or wattage...anything else i would say check your ground turn down all controls and dont upgrade your fuse...check first u dont wanna fry the board on the amp...use the recommended...hit me back if nothing else works...i got plenty more...

[TrailChaser]

*UPDATE*

 

I bridged the amp and put the 15amp fuse back in. Sounds 100% better and hasn't blown the fuse in over a week.

 

Thanks a million to everyone who helped out.