Keep Blowing Subs, Advice Please

[Joeh312 10+ year member]

Yo All,

I know my post counts low and such but I try and keep my mindless posts off the boards but with this one I'm fairly stumped.

So about 3 months ago I was cleaning out my garage and found an old, not very good, amp. The amplifier, which I don't have the current model number for because I'm too lazy to walk downstairs and look at it right now is rated somewhere in the neighborhood of 350w @ 2ohms.

So being my cheap self and not having much extra cash I decide i'll go ahead and throw it in the car (since I didn't have a substage at the time anyways) and use it for whatever. I had it installed by the same people I always have do my stereo stuff (because I'm super paranoid about my car and don't want to mess it up). I am using a well built box at about 2.5^3 ft around 32hz. First I had the amp matched with a Treo Tsi12. My understanding was I was overpowering it a bit but I figured I wouldn't have much of a problem after tuning. On my headunit I have the subwoofer with a LPF at 80hz and on my equalizer I turned the bass curve down to a -4 and used the built in subwoofer volume to a +3. Sounded wonderful for about a week and a half, everything was gravy then it got quite distorted. I immediately turned the subwoofer off from the headunit and went to inspect it. There was a noticeable smell and the cone would not push in. Immediately I figured i'd just fried the coils from overpowering it.

I went back to the shop I get most of my stuff from and the owner was kind enough to replace it immediately with no questions. 2 weeks later, same situation. I took it back once again and I was told there was a problem with the glue with the entire shipment he had gotten of Tsi12s. Afterwards he gave me an ID12 to fill in for my troubles. 2 weeks later, the ID12 blew with the same situation.

I KNOW that I was not putting enough power to the ID12 to blow, maybe the Tsi's but not the ID. I was not clipping off my headunit as I made sure to find the limit directly after firing it up after install. I don't recall listening to any type of music for a sustained period of time that reached below the tuning frequency...

So...any ideas on what could be causing my problem? I'm stuck now with a blown ID12 and a still working amp. The amp still powers up with the car and I can still turn the subwoofer on, it just sounds terrible..

Joey

Cliff notes: Old amp was found

Installed it with a Treo Tsi12, blew in 2 weeks.

Replaced immediately with another Tsi12, blown in 2 weeks.

Replaced with ID12 blown in 2 weeks.

Need input.

Click to read more...

 

[XanderMoser 10+ year member]

So I assume the shop set the gain on the amp?

You need to look at the amp, let us know what brand and model it is. What are the preouts on your HU rated at? It's possible that your gain was set too high, thus causing the amp to clip and the subwoofer's coils can't handle the constant voltage, so they burn.

 

[NhustlaR 10+ year member]

gain too high=distortion=clipping=blown sub.

the install shop prolly cranked the shit out of your gain. does your amp ever get hot?

 

[Joeh312 10+ year member]

Headunit is the Kenwood MP-635U with 3x 2.5v Preouts.

Amplifier is Sony Xplod Xm1502XS wired to Bridged, and to previously edit it produces 150w Bridged at 2 Ohms.

And Yes, the Shop adjusted the gain, they had the tools, I did not.

At this point I don't mind doing some work on the car anymore since I've gotten alittle bit more experience since then. Is it possible that my amp could be leaking DC current thus destroying any subwoofer that I put in? If so, how would I go about testing something like that?