[DamonZ28]

All of the sudden I'm getting very little sound from my subwoofer. If I put my hand on it, there's a little bit of vibration coming from the speaker. I checked all of the connections at the amplifier, and all of the connections inside the sub enclosure, and everything seems tight. What else do I need to check?

[Zr8000]

Fuses in the amp. If those are good and you have good signal to the amp, either the amp failed or the sub burnt a voice coil.

[DamonZ28]

Originally Posted by Zr8000

Fuses in the amp. If those are good and you have good signal to the amp, either the amp failed or the sub burnt a voice coil.

I checked the fuse on the amp, and it was intact. The letters on top of the amp light up, and they're still lit. Guess maybe I need a stereo place to look at it.

[ctrlz]

disconnect one of the speaker connections and put a meter across the subwoofer terminals. Use the lowest ohm setting. You should get either 2 or 4 ohms (approximately) depending on the impedance of your sub.
The low output sounds like a major malfunction. Speaker voice coil more likely to go than amp.

[DamonZ28]

I put a multimeter on the speakers, number was right (right around 4 ohms for a 4 ohm speaker). I put a 9 volt battery on the speaker inputs, and got the scratchy sound which indicates the speaker is still good. I noticed that the power light wasn't coming on at the amp, even though the color lights on top were turning on. I put the multimeter on the power & ground inputs on the amp - and it read 5.5 volts (should be at least 11 volts, for anyone interested or facing the same issue). Battery measured 12+ volts, and it reads 14+ volts on the dash while running. Weird. The amp & power cable fuses were both good. I decided to loosen the ground cable, wiggle the connection, and tighten it back down. I guess that was the ticket, it now works great again.

[ctrlz]

You could try a little anti-corrosion gel on that ground area:
https://www.amazon.com/Super-Lube-82...s%2C299&sr=8-2

[DamonZ28]

Thanks, I bookmarked it. I don't think anything is corroded, if anything maybe I should have sanded the area a little. It's only been hooked up a couple of months. It's grounded with my line out converter.

[keep_hope_alive]

You need more contact area for that ground, and to bare metal and not painted metal. You could get a grounding washer (the spikey kind) and keep the amp ring lower than that control wire ground.

I typically use masking tape to identify the contact area of the amp ground ring, then remove paint for that area only. You need a low-resistance connection for the amp ground or you will get heating there (resistance + current = heat).

[DamonZ28]

Excellent, thank you for the instructions!! I like the idea of a grounding washer, so I'll either get one of those, or hit the area with a little sandpaper. And I'll switch those wires around too so the ground wire is on the bottom.

[pzoom]

You need to take a grinder and get down to bare metal. Any resistance on the ground just reduces the amount of power available to the amp.

Just to throw out a random number, if the connection is 1ohm, then you are dropping a volt for every amp you are trying to deliver. Huge power loss especially for a sub amp! You can also have ground loops that will increase noise/hum.

[DamonZ28]

Originally Posted by pzoom

You need to take a grinder and get down to bare metal. Any resistance on the ground just reduces the amount of power available to the amp.

Just to throw out a random number, if the connection is ~1ohm, then you are dropping a volt for every amp you are trying to deliver. Huge power loss especially for a sub amp! You can also have ground loops that will increase noise/hum.

Yep, I'm going to do that next week. Then I'll take another measurement of the power coming into the amp to make sure it's where it should be (11-12 volts I believe).