The "thump" sounds like a loud clip, and I'm wondering if the amp itself has some sort of trip circuit built into it for protection. If it were thermal based, it would reset itself in time.
All I can say is that if I turn off the subs, I have to wait several minutes before they "work" again. The light comes on, but there is no amplification. If I wait, then turn them back on, no problem.
The replacement amps for the EP800s came last week, and I finally had a chance to install them yesterday. First, I have to say I was shocked when I saw how big the boxes were! They were shipped in EP400 boxes, and each amp was bolted into a dummy speaker enclosure, with a with a cover screwed on it! To get the amp out involved removing 4 screws and 4 hex bolts. It was extremely protected to say the least.
Following the directions provided by Axiom, I decided to remove the amp from the EP800 I had more problems with first. In my original post I stated that I had the thumping problem when turning the sub on an off. Afterwards, I noticed that the left sub would make a flapping" sound during certain LFE parts of movies (The Nemo fishbowl scene being one of them, Micah noticed it as well during the audition).
When I removed the amp, I followed the directions to double check the wiring connections internal of the speaker to the 2 drivers. I wanted to do this anyway because I noticed that one of the drivers (top) did not move as much as the other (bottom). The wiring connections looked fine on the bottom drive (+/- on bottom of driver, AND +/- on top). When I looked up into the enclosure at the top driver, I noticed 1 wire was disconnected! I could not reach the driver from the amp opening, so I removed the top driver. Low and behold, one connection was disconnected on the bottom of the driver (-), and one connection was disconnected from the top (+). So, this whole time, the amp was only driving one of the drivers, and the top drive was acting as a passive radiator. I quickly reconnected the wires and tightened all connections. Then I put in the new amp. The other speaker's connections were fine, so I only had to replace the amp.
What's the verdict? Well, no more thumps when I turn the speakers on and off! Also, for the sub that had the connection problem, both drivers now extend the same amount when driven. The final test was the Nemo fishbowl scene... No more flapping during that scene!
Thanks to Axiom (and Alan especially) for sending me the new amps and reminding me to check all of the connections to the drivers as a precaution. I'm a happy man!!! Well, that is until I remembered I have to bolt in my old amps to those huge shipping enclosures!
