jdtypeS

I got the system hooked up and everything, but the amp is LIKE FIRE!!!!!! Kid who helped says its because its 4 channel amp, and all i need is a 2 channel (powering subs only) . True???

mcdanjw

Tell me briefly how you hooked it up... like what channels are powering what speakers kind of stuff.

jdtypeS

He tapped the RCA's from the back speakers, instead of Head Unit. And he has just the right channel and left channel hooked up to the amp. Im not sure what all he did. It sounds awesome, but the amp is sooo hot and it worries me. If you can like ask me something by me looking @ the amp and then telling you i can.

mcdanjw

A couple of questions...

He did use line out converters to tap the back speakers? You'd see a small black box on the wire between the speakers and the amp.

Does the amp get really hot after you've been playing it loud for a while or does it get hot just by turning it on?

It shouldn't hurt anything to only use 2 channels of a 4 channel amp.

OUTRAGEOUS CL TYPE S

ITS A 4OHM SET UP PROBABLY CONNECTED THE WIRES IN THE WRONG SOCKET OF THE AMP.

RMGCL-S

Depending on what kind of amp you have, the amp is getting really hot because the four channels are bridged down to two, creating, most likely, a two ohms load for the amps. Check how the kid wired your subs (if they are two eight ohms subs in series then its four ohms). The amp is getting hot because it is running at a lower resistance than what it is made to handle.....This is NOT a good thing...eventually your amp will blow. Have a professional rewire your subs for the proper ohm load. Hope this helps

SilverKnight

tapped RCA cable to the speaker lines? and you told me he owns a shop? I wouldn't take my car there. First the "high pass, low pass converters", now using speaker level inputs as line level???? He sucks

SilverKnight

ummm ... when your bridge the channels you dont lower the impedance load. If you wire 2 8 Ohm subs in series you are looking at 16 Ohm load. Dude, you get everything reversed except for running the amp at lower impedance load would make the amp hot.

JD, I think your friend has no clue what he is doing. He keeps bullshiting.
1. Told you to get "high pass and low pass converters". I wonder if there is such things
2. Using speaker level inputs as line level inputs.
3. Told you running only 2 channels on a 4 channels amp would make the amp hot.
4. Used a battery tester to test subs. (Maybe I'm studid on this one but I know ppl use an AA battery to test for sub's polarities)
I'm sorry but I have to vent. Using only 2 channels on 4 channel should not make it hot. As a matter of fact, it should be cooler since there is no load on the other 2 channel. RF amps are pretty good when it comes to driving subs. I suggest you find a guy who knows how to do car stereo (I meant really know) or take it to a shop (not your friend's shop though). Good luck, dude.

jdtypeS

1. The high to pass converter thing was to convert the RCAs.
2. Using the speaker level inputs as line inputs, i dunno wtf he did that for...
3. I thought it would give less heat also since there are more channels.

He doesnt have a shop, but he hooks up people's systems and builds boxes and stuff. He has an ad in the paper, but its more of like a hobby than business.

Would it be better if i used a 2 channel amp? Thats what hes telling me.

He hooked up the subs where it looks like the wires are doing a BIG X on the back of them.

Could there be something wrong with the amp?

mcdanjw

Just wanna make sure I'm following this thread...

So he did use line output converters hooked to the rear speaker leades to get the inputs to the amp?

Does it get hot immediately or after you've been playing it loud for a long time?

NOLACLS

Its probably the ohms....you want to stay at a 4 ohm load...amps run much cooler this way and dont go into thermal protect. Have the ohms checked.

jdtypeS

Yes, im pretty sure.

We had it on for just a little bit, while he was changing like the gains and stuff to make it sound good, and it got sooo hot in just a little bit of time. Im thinking, im just gonna return it and get a 2 channel amp. Seems like the easiest way.

mcdanjw

Okay, do you know what the impedance of the subs you have are? 4 or 8 ohms. It should say on the back of the speaker somewhere I would think.

Since most car amplifiers are designed for a 4 ohm load, if you have 8 ohm subs and are just running them in a normal setup (not parallel or series wiring), your amp will get overly hot because the load is too high.

Does that kicker sub comes in either a dual 2 or dual 4 ohm voice coil. Do you know which one you have?

This would make the amp work twice as hard for the same volume level of a 4 ohm setup.

SilverKnight

When you run a higher impedance load, your amp runs cooler not hotter, however, the volumn is lower by the load factor.

RMGCL-S

Dude, the ohms load has to do with the wiring of the subs. It also has to do with how the subs are wired into the amp. If the are wired for a 4 ohms load and you use a four channel amp that is bridged down, the actual ohmlaod to the speakers is 4, but the amp sees and ohmload of 2 (because the amp is bridged from 4 ohm stable to 2 ohms) Your amp is getting hot because the amp sees the 2 ohm load and overworks itself. And a hi-low converter is a unit that converts a high frequency sighal from a stock HU (signal going to speakers) and converts it to a low signal to run a sub amp.

Woodsdaddy

If you use a 4 channel amp to run two woofers that doesn't mean they are in a paralell circuit. They are most likely still in 4 ohms unless they are dual voice coil. Keep in mind that heat in electronics is caused by the dissipation of power. Also the heat sink on RF amps is the top.

mcdanjw

The kicker speakers he has are dual 4 ohm voice coil. He wired them in parallel, which drops the impedance of the speaker to 2 ohms. He then hooked up each one to one channel of the amp, effective running a stereo setup.

This is why his amp is getting hot.

But I looked at the specs of his Fosgate amp, and it is stable at 2 ohms.

So, this is not hurting anything.

Changing amps will not help.

It's the speaker setup that is the culprit.

I would leave it alone, and if you have problems with the amp shutting off because it's getting to hot (it will shut itself off if it gets to hot), then look to either replace your speakers with ones that can be wired to produce a 4 ohm load, or put a fan on the amp.

Woodsdaddy

why not run each voice coil to one channel of the amp. It will run cooler and sound cleaner.

mcdanjw

That's an interesting idea... never thought that way, I've always seen the voice coils stranded together before the amp.

Can you do this without hurting anything?

Does the stereo signal have to be exactly the same for each voice coil to keep from damaging the speaker?

Anyone know?

mcdanjw

I love it when I answer my own questions!!

http://www.jlaudio.com/tutorials/dvc/dvcAdvantage.html


You are absolutely right! Wire each coil separately. This will create an overall load of 4 ohms on the amp and use all the channels. It will put out the same power you are getting now, and won't run anywhere near as hot.

Though be sure to get all the +'s and -'s right on the connections or you can damage the speaker.

jdtypeS

I called up kicker's tech assistance to see if i could hook it up independantly(like you suggested) and they said they wouldnt reccomend it but theoretically i could do it. But i would have to make the freq. below 100hz and not to hook it up out of phase or it wouldnt work.......

Woodsdaddy

I don't think you would want anything above 100hz on the subs anyway, it would be a little muddy. I think this is ok as long as both coils are running from the same amp. It should be the same amount of power on each channel of the amp.

mcdanjw

You could make sure the amp is putting out exactly the same signal through both channels hooked to each voice coil by using a y-type splitter on the input. Only use the left channel signal for the 'front' portion of your 4 channel amp and use the right channel signal for the 'rear' portion.

Then wire one sub to be 'front' and one to be 'rear'.

That would ensure that both voice coils get the exact same signal.


That JL Audio tutorial on dual voice coils was talking about using both the left and right signals wired to a center channel speaker. Sounds like the speaker should be able to handle sight differences in input anyway, as long as the speaker is wired to be in phase.