So,

Saturday, I was installing my subs and amp and among a myriad of problems, My most glaring problem to troubleshoot is a sub thump (more like: thump thump, thump thump, thump thump) and my amp going in to protect. The problem is, this happens long after everything is turned off. As a matter of fact, I went in to Jack in the box, ate, came back out 20 min later just in time to hear it.

My setup is

- 6 SA 8's D4's

- 2 1500's

- 300 amp alt, 1 CnD 100ah, 2 XP 3000s

When I initially wired the setup, I paralleled them (2 sides of 3) for a final resistance of .67 per side and ran both amps strapped (I initially thought I was at 1.67 per side).

Since I was worn out from getting everything in, in the first place, I did a half ass job at troubleshooting, but this is where I'm at:

- Voltage at the amp was 15.1/13 volts with the car on/off.

- Resistance at the speaker terminals was .6 (wound up @ .3 when I strapped the amps)

- After I encountered the sub thump with the amps strapped, I switched everything to one amp and had the same problem.

- Resistance at the sub terminal was 20 ohms(wtf?), but it was .6 at the end of the speaker leads. It was also .6 at the amp.

- Grounds were good. Amps are hooked directly to the back batteries. Back batts are hooked to the front, big 3 done.

What I plan to do

- Since I'm going to gain match the amps now, I had 2 grab another rca set, so I went ahead and grabbed 2 so I can switch out both sets.

I'm hoping I just have a bad RCA set. Also everything was brand new from Sundown, just got it earlier that day. Any other ideas where I should look?

This happens when the car is off? Doesn't seam like it could be the RCA's.

Your amp goes into protect when the car is off?

Are amps off when it thumps?

Are you using a high to low signal adaptor?

Oh yea, I guess I left out an important factor. My relay went bad, so I had to switch my remote wire from 12v switched to 12v constant. I would unplug the remote when I got out the car (I forgot to when I ate).

I'm changing the relay with the RCA's.

Amps are on.

Oh yea, I guess I left out an important factor. My relay went bad, so I had to switch my remote wire from 12v switched to 12v constant. I would unplug the remote when I got out the car (I forgot to when I ate).

I'm changing the relay with the RCA's.

So amps were on when it thumped. Are you using a signal adaptor?

Signal from the HU goes through my RF 360.2 to my amps. Car and HU were off and the 360 was off when the thump occurred.

Are you using high level inputs?

Sit in the car leave everything off except leave the amp on like before. Open and slam the door. If the subs thump it's just the signal that's created by the coil in the door speaker back feeding thru the 360 into the amp.

I'm using low level inputs. The doors were open the first time it bumped and closed the 2nd.

So to update the situation,

I got my new RCAs in (by the way, I'm very impressed with these NVX wires from sonic). I also got in my new spdt relay. While swapping those out, I did notice that the fit of the older RCAs was alittle lose plugging into the sig pro. After that, I double checked my connections and let her rip.

Everything seems to be working fine now although I find it hard to believe it was the rca connection causing the thump since there was never anything that could agitate it (360 is under one of the back seats, no one was near the truck when it happened). Oh well, if it comes up again, i'll update.

The 360.2 can cause thumps.. our 360.3 will do it if youre using the remote out on it because it'll shut the amp off with a delay from the hu.