hi guys. so i finally got my sub installed ( alpine type r 8) on the rear channels of my 300/4. everything was fine for about a week and then my sub started making a weird low popping sound when i would first turn the radio on. it would play fine after a couple seconds and bump real clean. Then today it totally stopped working and my amps low ohm light came on. anybody have any idea whats going on with this amp? Jl will not fix it due to it having no serial number sticker on back. bought it at yard sale and didn't see this. please advise me. thnks in advance

 

Since it's a 300/4, I'm presuming you have the front channel connected to the front speakers and it's still working correctly? That would indicated the problem isn't with power but I would start with double checking the power connections and then double check your speaker connections, both at the amp and at the speaker to make sure they're solid. Double check the speaker cable too in case it has a small break in it you can't see.

The low popping noise sounds like bad news to me. Do you have a multimeter? Set it to AC volts and put it between the positive and negative of each channel and see if the voltage increases as you turn up the gain. If there is no voltage at all or the reading is very low it could be an indication. You should be able to do this with or without a speaker attached, just watch the gain especially if a speaker is attached.

I'm assuming that you're bridging the sub to the rear channels. What happens if you connect it to just the left rear or the right rear?

Have you tried anything like disconnecting the front channel from the front speakers, and connecting the sub to see if it works? Likewise connect rear channel of the amp to the front speakers.

Next to that you'll have to take it in and have it serviced which may not be worth it.

 

thnx for all your solid advice. didn't test it with a dmm. I tried every configuration I could but no dice. I don't know if its related but this amp got extremely hot, which always worried me . I think bridging this amp for a sub may be a idea, to be honest. I was never comfortable turning up the volume. this whole ordeal actually pushed me to buy something better (jl 900/5). now I have plenty of power for both comps and sub and doesn't get too hot. and I'm super happy. thnx again

 

If it got extremely hot and then it failed it's probably done for, so good that you moved on to something better. It could be part of the reason it was for sale at a yard sale.

I only mentioned bridging on the 300/4 because I presumed it was connected that way, as that would be the ideal way to power a single sub with it. With the 900/5 you have more power so with a small sub it might not be worth bridging, I'm not sure, depends on the wattage of the amp and power handling of that sub. You said the sub isn't getting hot anymore, did you mean the amp or the sub speaker itself was also getting hot? If the sub was getting hot that could be a new variable. As long as it's not getting how now though, that should mean there is no problem with the wiring or in the speaker itself.

 

yeah. amp was getting way hot not sub. now I worry I may be overpowering my lil sub with the 900/5.(100x4 + 500x1) type r 8 is 300 RMS. anyway, I will take it easy as I am still learning car audio. this forum is where I get most of my info and the guts to do it myself. thnx again.

 

Just wondering though why would you have a sub hooked up to the 300/4? The 300/4 is a mid range amp. I am running a 300/4 to push my Boston Acoustics and a 500/1 for my 12W6V2. The sub might have been too much for the channel and the amp must have gone into protect mode (yellow light).

 

The 900/5 (HD I'm assuming) is a great amp for the price. You can always turn the gains down on the amp so that you don't overpower the sub. The good thing about the 900/5 is you have enough room to add to your audio setup (ie. adding components etc) I'm actually looking into one of those now so I can have one amp to do everything.

 

Yeah, being a total noob didnt help my situation. It was suggested to me that i run that setup until i could afford a bi-amp system. Comps on front channel and sub on rears. Obviously, the type r was too much for it. I chose to stay with a single amp setup and the hd 900/5 is everything you need in a small package. Awesome amp! I plan to go bigger sub (maybe 1 10") in near future. Its nice to be able to upgrade and have plenty available power. Question for you: would you do rear speakers in a sedan. Not sure if it would be too much mid and highs but the the rear channels are being wasted at the moment. Thnx

 

It all depends on what you want to achieve as far as sound...everyone is didfferent. I had a coupe which I eliminated the rear deck speakers. I used components in the doors and rear quarters and didn't use anything for the 6x9's. For bass I used 2 12W6V2s. The mid range/voice speakers were powered by a 300/4 and the subs were powered by a 1000/1. Don't look at it as a waste though because the am is built to support a full system.

 

I think ill go bigger sub first. Then i can decide if rears are needed. Are you happy with jl 12s ?

 

Rear speakers aren't needed. Without a dedicated sound processor it's going to reduce the sound quality. Music is mastered in stereo, not quadraphonic. Leave surround sound to movies and TV mastered in surround.

 

Fronts only it shall be. I didnt wanna spend any more money on highs if its not gonna be beneficial. The 900/5 wasnt cheap. 1 ten and call it a life. Open to suggestions on ten sealed

 

Sundown SA-10 or Image Dynamics IDQ10v3.

 

Ill look at those. Thnx wrathernaut