Q First of all, I love your magazine. I am experimenting with different systems in my '94 Mercedes-Benz E-320. Currently, I am running two Memphis M Class DVC subwoofers powered by a Memphis PR 150.2 amp. I purchased a Kicker Solo-Baric L7 and realized that the Memphis amplifier wouldn't power the Kicker. To give the sub what it needs, I bought a Power Acoustik TS1440-2 Plasma Sphere amp that would provide 720 watts when bridged to a 4-ohm load. I hooked it up to the Kicker (wired series to be 4 ohms) and it was loud. Then, the amp switched to protect mode and won't switch back. I looked at the amp's nternals and nothing is fried. I also unhooked and rehooked the amp and it won't reset. What can I do to fix the amp and get it out of protect mode?Thanks,Chris
A It's a good sign when your amp doesn't visually appear to be fried. When an amplifier fails dramatically, internal parts will burn due to excess current. Unfortunately it doesn't end there. Heat generated by the failing part will often burn the circuit board material, causing it to carbonize. You wouldn't think that a bit of charred circuit board would be a big problem, but when you consider that resistors are also made of carbon, you can make the connection-the circuit board that was once an insulator now has a built-in resistor that is connected across too many circuit paths. While you may be looking for burnt components, be sure to check the board itself for signs of heat. If the circuit board is burnt, the amplifier is likely not repairable.
In your case, it sounds like a much simpler problem. If the amplifier is in protection mode, then the first item to eliminate is the speaker. Disconnecting and re-connecting isn't the answer, because if your speaker has a shorted voice coil, you're simply re-activating the protection circuit when you reconnect the speaker. You need to connect to another speaker that you know functions. You don't need to play it loud, just confirm that your amplifier has reset and plays. Then replace your defective speaker.
If the amplifier won't reset, even with a good speaker connected, the amplifier has likely had the protection circuit lock up. This can be related to a few different situations. In one case, the amplifier may have a manual reset or replaceable protection device-something like a fuse or circuit breaker. This needs to be repaired by a technician since you probably don't have the training or equipment to find the defective part. Another situation is that a semiconductor has failed in the protection circuit. Without burn marks, it will also require a technician with the skills and equipment to isolate the part.
If you do find that the speaker is the cause, you can be fairly sure of one thing: If you replace the speaker, the same situation is probably going to happen again. Loud is fine if the speaker system isn't being killed in the process. You won't recognize that damage is occurring, since it will take a minute or more before the speaker's voice coil fails. Plan on increasing the number of subs so that they can distribute the power while providing even more output.
Q I'm trying to run two 12-inch subs off of a two-channel amp. I have everything hooked up, but the right channel of my amp isn't working. I can hook both subs to the left channel and they work, but I don't feel comfortable with it. Is it safe? Thanks,Andy