This evening's setup has gone wrong.

[Josh_Dude83]

Hello. This is my first post so go easy on me. So i was finally hooking up my amp/cap/sub setup. Everything was going good after setup, but the sub wasn't hitting as hard as i thought it should. I was tinkering with the gain and nothing. Let me state now the amp is a 2 channel RF punch 300s, should be 150x2. So after not getting much of a response I went to my head unit to tinker with settings. My head unit is a sony cdx-gt09. After fiddling with the settings I realized this head unit doesn't have a designated sub output and only by turning up the sub on the speakers does it also adjusts the sub. I turned sub to max on radio and then I got a little more hit out of the sub and decided to go back and turn up the gain on the amp. I started with channel 1 and slipped on the gain knob and cranked it. The sub hit really hard for about 4 sec then went dead.

So the dilemma here is where to begin testing to see what went dead sub/amp/fuse etc. The radio seems to be working fine. The amp is wired to the box with terminal 1 and 2 + combined to + on box, and terminal 1 and 2 - combined to - on box. I wanted to see if the amp was still outputing to the sub so i checked voltage at the sub box and was reading a constant 20-23V. The amp was still warm to the touch as well. I haven't found any fuses on the amp so idk what to do with that. Thought they usually had a fuse.

Even though the radio was still going I know there is a fuse on the back of radio and made me want to make sure there was still a signal from the radio to the amp but wasn't able to get a read on the input cables to the amp...any suggestions. I put voltmeter on the the male part of cables and then to outer ring and couldn't get any voltage reading. Yes the cap still has a solid voltage reading so I know I at least have power to there and to the amp. The amp LED is still on as well.

Next I took out the sub to find that it was a dual coil 2ohm 400W RF sub. The sub is wired: box + to terminal1 +, terminal1 - to terminal2 +, terminal2 - to box -. Where do I need to put the voltmeter to check the ohms and what reading should I expect?

I guess that is the most information I can give. Thanks in advance for any and all help in resolving this issue.

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[chillin 10+ year member]

did you smell anything from the sub when it went dead?

 

[Josh_Dude83]

no no smell. It's still warm too. Idk.

 

[BlactimusCrime 10+ year member]

unwire the sub completely, and check the resistance at each coil, should read roughly 2ohms each side, if goes really high, the coil is fried.

edit: and get rid of that **** cap.

 

[Josh_Dude83]

alright. I will do that in the morning. So now, if the worst has come to pass and the sub is fried what kind of replacement sub should I get so it doesn't blow again for the amp I have if it's a 4 ohm amp wired as I said to the box. Dual coil single coil? Wiring? I dont want this to happen again lol

Now sure how a 150w amp blew a 400w sub. Can someone elaborate for me please? Does it have something to do with the wiring?

 

[Mitch86 5,000+ posts]

alright. I will do that in the morning. So now, if the worst has come to pass and the sub is fried what kind of replacement sub should I get so it doesn't blow again for the amp I have if it's a 4 ohm amp wired as I said to the box. Dual coil single coil? Wiring? I dont want this to happen again lol
Now sure how a 150w amp blew a 400w sub. Can someone elaborate for me please? Does it have something to do with the wiring?

"Cranking the gains" is where you went wrong.

 

[LiveAudio911 10+ year member]

Distortion.. Clipping.. and so on.. The sub was not broke in... sent max power to the coil at once.. many things could of happened.. but I guarantee it was overpowered in one way or another..... being the sub is not working..

 

[hispls 5,000+ posts]

Technically it's a 300W amp and it can easily blow up that sub if you "clip" the signal (search clipping for technical explanation that I'm too lazy to type) in layman's terms if you attempt to run more power out of that amp than it's capable of (by throttling up the gain all the way) as far as the effects on the woofer you might as well be throwing 600W at the sub.

Hopefully you didn't hurt the amp at the same time.

Alpine type R is a much better built sub for about the same money, or you can shop around the classifieds section here for a good deal on some used gear....hopefully you bought the sub from a big box store and can get a return.

 

[chillin 10+ year member]

If you crakn the gains, the amp will produce more than 150 watts. It will clipped watts, but more none the less. From what I undersatnd clipping creates a lot more heat than normal signal, which will lower the subs thermal power handling aswell as the amp putting out much more power than 150 while it is clipping could = blown sub. I'm not 100% on this but worst or one of the other more knowledgeable guys im sure could correct me

 

[LiveAudio911 10+ year member]

You put a single DVC sub on a two ch? thats your problem then.. you cranked the gain on one of the coils while the other coil was stable..

This is why you should run mono amps for subs..

The clipping thing:

Think of it like this.. The output of an amp or any stereo is an electrical current.. when you start turning up the gains once you have adjusted the gain to match the out put of HU, the output of the amp is at its peak electrical alignment... once you go past that point.. and increase beyond you start throwing dirty current above what the amp can safely produce.. in the form of distortion.. clipping.. subs can react with muttled signal, poping sounds,... overheat and melt the coil.. a lead into the coil former.. melt the former or other part..

That should put it basically in perspective...

 

[Josh_Dude83]

You put a single DVC sub on a two ch? thats your problem then.. you cranked the gain on one of the coils while the other coil was stable..

I combined both +'s of the amp to the sub + and both -'s to sub -. The dual coil terminal has 2 terminals wired as I said in the original post. So i dont see how cranking the gain on one channel of the amp would blow. It would have been shared by both coils?

 

[chillin 10+ year member]

You put a single DVC sub on a two ch? thats your problem then.. you cranked the gain on one of the coils while the other coil was stable..
This is why you should run mono amps for subs..

The clipping thing:

Think of it like this.. The output of an amp or any stereo is an electrical current.. when you start turning up the gains once you have adjusted the gain to match the out put of HU, the output of the amp is at its peak electrical alignment... once you go past that point.. and increase beyond you start throwing dirty current above what the amp can safely produce.. in the form of distortion.. clipping.. subs can react with muttled signal, poping sounds,... overheat and melt the coil.. a lead into the coil former.. melt the former or other part..

That should put it basically in perspective...

As long as the coils are wired together inside the box it shouldn't matter. He said he wired to the box. Sub is probably wired to parallel

inside the box. Also a two channel amp wired to one sub is bridged, which is fine as long as the amp can handle it.

 

[Josh_Dude83]

Yeah, what chillin said. SO that's why i was surprised the sub would blow by turning up a single gain. If anything maybe amp is bad?

 

[chillin 10+ year member]

However its a dual 2 sub from what i read and alot of 2 channel amps are not 1 ohm stable bridged, so if you wired the sub to 1, you could have facked up the amp

 

[Josh_Dude83]

idk. Dont have money to replace both, nor do have any spares lying around to figure out what is bad and what isn't. No they weren't bought new. Got from a friend when he moved out.

Going to do myself a favor and pick up a mono amp as soon as i can. Less wiring is good!