Ryan Bickley
Hey guys, first post here, I did have this posted on DIYMA as I thought that they would have more experience then my local forum, no one has replied, so I am bringing it here.

This is going to be a long post.
On the weekend, we had the first comp with our newly rebuilt SPL car.

Not all went to plan.

The car is a 1989 Ford Laser

We are running 4 x 15" Audio System Helon Subs [dual 2 ohm]
2 Audio System Helon 9000.1 amps
And running it off of 14 Trojan 8 volt cells
No alternator was used, nor was plugged in

So we were floating around 16.3 Volts at the amps.

We wired up the amps and turned them on, both of them powered up [they were strapped] So we connected the subs to them [wired at 2 ohm per board] Turned it on and all was still well.

We had a multimeter connected to the power input at the amp, plus a seperate readout on our headunit, voltage never dropped below 15 volts.

We had a clamp meter on the output, the highest it read was about 2 volt output.

I dont recall maximum amperage draw, but it never hit double digits

During connection of the amps, the bottom amp [one that had been used previously, was slave and second to blow] this sparked on connection. The second amp [Master amp, never powered up, etc] Did not spark on connection.

We slowly turned up the gains, it was at a moderate listening level when there was a loud bang and the master amp went into protect and wouldnt come back out. There was the smell of burning electrics. We disconnected the amp and checked over everything, we couldnt find anything wrong.

We pulled out the amp and rewired the second one to 1 ohm at the amp. Went through the same procedure and the same thing happened.

We checked and rechecked everything during the entire course of events. Both before and after. there was a 12 volt remote, everything was wired correctly. No fuses were run, this is after all SPL.

The first amp had not been tested and was brand new, unused, the second had been powered on a 12 volt setup and had run.

Both me and my team mate are trying to work out what went wrong, how it happened, whether it was something we did or something else.


Had them sent to a local electronics store to have them looked at, apparently all the FETs [all 32 of them] on both amps are fried.


If anyone can throw any light on this, that would be most appreciated, I have tried to provide as much information as possible, but if there is anything I have left out, I will be happy to give it.

When I can find photos I will put them up, my friend still has them on his camera.

Thanks, Ryan
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Team DD Belgium - Dieter
Was the ground of the 12v and 16v system connected with each other?
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stany
Quote:
Originally posted by Team DD Belgium - Dieter:
Was the ground of the 12v and 16v system connected with each other?
^^ indeed verry important

If the answer is negative; the 12V remote system can impossible make ground : what can create nasty things ...
[stanystats]
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Ryan Bickley
Yes, they were both earthed to the chassis, I have tried troubleshooting everything I can think of and can think of nothing that would have caused it to happen..

Thanks for the quick answer though
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Ryan Bickley
We still dont know what caused it, the company who are fixing it have no idea what happened to them.

On another note, I wonder if anyone could throw any light on what is going on here..

One of our subs [Audio System Helon SPL 15] seems to be 'losing' resistance in its coils. They were dual 2 ohm coils [1.9 each] But we noticed that one of the coils was measuring lower then the other one and all the other subs. Checked with several multimeters, and they all show the same thing, one coil was reading as 0.95 ohm. Then the other day, did a bit of testing, decided to check impedences again, and now both coils are reading 0.3 ohms each. All the other subs are still reading 1.9.

Could this have caused an issue with the amp/s, how does it happen, and how do we fix it? [recone?]

Thanks, Ryan
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stany
Hi Ryan,
this all sound a bit weird.

I would advice to check everything out double before get that system rolling again; before more is damaged then needed.

Coils that are lowering in impedance is not a Normal or common thing; probably the coil is somewhere rubbed and regards that some layers of wire can make contact what results in a lower impedance.

If you push in the center of that particular sub : do you here it rubbing or do you here a scratch sound ??

I would definatily check everything, because Yes this can cause the amp(s) to blow out regards you short almost the outputs. And it would be logical then to what happened with the amp(s).

Fixing sub(s) can only be done with recone(s)

Btw, how did you connect the subs to the amp? I read you strapped the amps, so i like to see a little drawning how you did connect it all.
[stanystats]
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thanosdbfan
Are the amps 18V version?

From what i read i am pretty confident that the Voicecoil of that sub is causing a short circuit (propably from worn insulation resin.)
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Ryan Bickley
Thanks for the replies guys, as far as I know, they are the 18 volt version, the manual that comes with them states the input as being upto and including 18 volt.

We pulled apart that sub, it wasnt rubbing at all, and right near the top of the coil there was a short, it looked like it had a nick from the factory and had somehow rubbed through to other windings and shorted out between them. Will be reconing that one, and possibly the others [as they no longer make recones for this sub]

Will draw up a wiring diagram tomorrow if I get around to it.

Once again, thanks for your help guys.
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