strange subwoofer thumping problem

I recently got a new amp ( powerbass ASA 1500d ) which is 3000w max.
That is powering up 2 12inch Pioneer Premiers champion pro series..rated at 3000w peak and 1000rms each.
The amp is grounded with a 4 gauge.

I had a friend connect the amp and thought it was going to be a simple swap..but when we connected the subwoofers to a channel, the subs would start thumping out loud frequencies. All the knobs were turned down on the amp and the sub setting on the deck was set to -15. We also disconnected the RCAs from the amp and tried connecting..still it would make the subs thump like crazy. I also switched out the glass fuse for an ANL 200amp one, but still the problem persists.

any ideas on what is going on?

 

42 views c'mon guys! =)

 

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thanks!

 

Thumping out loud frequencies.....is not very descriptive. Got a recording of this in action? I can figure it out I'm sure but I need more information.

 

the subs will burst out into a continuous erratic thumping when connected to the amp. I disconnect immediately.
I'll post a video tomorrow..hopefully that will help a lot.

I really don't know how describe the behavior.

Before I put in this new amp, I was using a 1600w sony amp. The subs were fine . I haven't rewired the subs any different (bridged each subwoofer)

 

Sounds like you may have the Pos and Neg messed up or maybe you need to ground your RCAs also what is you OHMs

 

Pos and neg connection in the subs?

my ohms for the amp? I was trying to run them at 1ohm, but we couldn't even get it to connect, cuz the subs would just start thumping bass notes.

how do you ground your RCAs?

 

nvm..looked up how to ground the RCAs.. i'll probably just get a new set of RCAs tomorrow too.

 

Looks to me like you already know the answer. Try putting the Sony back in and see if they still work fine.

BTW alot of amps are not 1 ohm stable, not to mention theres very little reason to run at 1 ohm.

 

My guess was going to be that the subs were just playing a constant 60hz note but since we're not in the house that's not the case I'm sure.

Definitely check your wiring OP.

 

Symptoms sound like what I had when I hooked up my sub at 2 ohm loads, when the amp was not stable at 2 ohms bridged mono (even though the docs stated it was). Might want to re-wire to present a higher load (ohm) to the amp and see if that helps. Might be easier then re-installing your old amp.

 

Powerbass amp im using:
375W x 1 @ 4-Ohm
750W x 1 @ 2-Ohm
1500W x 1 @ 1-Ohm Mono Power
3000 Watts Peak Power

Subs i'm running
Size 12"
Max. Music Power (Nominal) 3,500 W (1,000 W)
Frequency Response 20 Hz to 150 Hz
Sensitivity (1 W/1 m) 90 dB
Impedance 2 Ω x 2 or 4 Ω x 2

I don't know if this helps, but how should I wire my subs to where they hit the hardest without problems?

 

Draw us a picture of how you have these wired. Do you have the dual 4ohm or dual 2ohm coils?

 

I don't remember which ones I have. I'd have to wait til tomorrow to take pictures of the subwoofers for they are not with me at the moment.

but let's say I had either 2 ohm or 4 ohm.. what exactly would I need to do?

I dropped off the amp at a repair shop so they will be getting back to me either later today or tomorrow and let me know what needs to be done.

 

When my sub blew for the first time it would hit randomly when connected.

 

i actually have a couple of pictures to how the subs were wired
I DO HAVE dual 4 ohms.





I hope these pictures somewhat help.

 

Can I get a close up photo of the terminals straight on so I can see your + and - labels.

It looks like + - - +

And if so, you're not wired correctly

 

The diagram shows how I have the subs wired currently.
So now that I do have the wiring correct, what else can be the problem?

I just bought some 0 gauge which I will be able to hook up the amp to tomorrow and see how that goes.

 

Wait.....stop

Bigger wire wont help
Different fuse wont help

You have something WRONG in your setup. Figure out what it is. Take a DMM (digital multimeter) and measure the final impedance of your subwoofer system. That means, take the two wires that are supposed to go into your + and - on the amp and measure the impedance. Is that you get close to 1ohm?

I'd suspect that the subs aren't the problem though since you had them running on the old amp and they were fine. Are you sure you didn't swap your power and ground wires by mistake when inserting them into the amp?