Need some help troubleshooting sub amp problem

[Mirage_Man 10+ year member]

I tried searching this forum as well as others and even the net but I can't find anything that is like what I'm experiencing. I'm hoping someone here can help me narrow down where the problem lies.

Here's my current system in a 2007 Toyota Tundra Double Cab. I'm running active fronts.

Alpine W200

Alpine H701

JL 300/4 bridged to Dynaudio MW162 Midwoofs

JL 450/4 150 watt channels to Dynaudio MD102 tweets. 75 watt channels to Polk Momo coax rears

JL 500/1 to a pair of Arc Audio 8D4's (4ohm load to amp)

What's happening is my sub is cutting out randomly but consistently anywhere from 4 mins. to 20 mins. after turning the system on. It seems like it will stop at any volume level. I've been running the system with no issues for a few weeks. This problem started suddenly. If the truck sits off for a few hours and I start it up the sub will play for a little while then back to shutting down. I have no idea if this is an amp, processor, HU or wiring issue.

I pulled out the back seat just in case it might have been a thermal shut down issue but even with the seat out the amp doesn't even get warm when pounding on the subs for a long time yet still eventually shuts down. The amp is still getting power and the power light is on. Neither the low imp or thermal leds light up. There is a fused distribution block feeding the amps. I pulled the one out for the 500/1 and plugged it back in while is was live and the subs started playing again. hmmm... If I turn the truck off and then back on right after it cuts out it doesn't come back on like it did cycling the power with the fuse.

I tried to measure voltage on the RCA's going to the sub amp when it is working but can't get a reading. How does one do that correctly?

Now I must mention that the H701 was purchased used from a guy over at ECA. When I received the piece it was apparent that it had been serviced by Alpine...twice! The guy claimed he had no knowledge of it and that he himself was not the original owner. I figured that Alpine must have fixed the problem and decided to roll with it. This of course might be of no consequence but I had to mention it.

Anyone have any experience with a situation like this? Or have a suggestion on where to go from here?

Click to read more...

 

[silvercookie 5,000+ posts]

you probably need a new battery cause if the amplifier is getting less than 11-12 volts it will shut off

i remember i had a small battery hooked up to my old amp in my room and even tho the headunit stayed on and played the sub amp would shut off and then the headunit would start to fade out.

see what the resting voltage of the battery is. if it is below 11 you either need a new one or just get a battery charger and charge it for a day or so and maybe it will hold a more powerful charge longer.

anyway what kind of battery do you have?

alternator?

and did you do the big 3?

cause three amps even tho they are not powerful and if they are not class d will draw alot of current

 

[azimuth 5,000+ posts]

you probably need a new battery cause if the amplifier is getting more than 11-12 volts it will shut off

huh?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif what are you talking about?

 

[silvercookie 5,000+ posts]

huh?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif what are you talking about?

i meant less than my bad.

edited.

 

[ultimate157 5,000+ posts]

you probably need a new battery cause if the amplifier is getting more than 11-12 volts it will shut off

huh?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif what are you talking about?

x2... The higher the voltage the better (Up to the amp's limit, of course)

 

[silvercookie 5,000+ posts]

x2... The higher the voltage the better (Up to the amp's limit, of course)

i edited it while you were posting lol.

 

[Mirage_Man 10+ year member]

Yeah I know JL's will shut down when the voltage is too low but the other 2 amps don't shut down. If the voltage dropped to the sub amp it would to the others as well which would then also shut off.

 

[silvercookie 5,000+ posts]

that is what i was basically saying lol.

 

[Mirage_Man 10+ year member]

OK here's the current report.

I hooked up my Soundstream Ref500S and it played with no issues. The SS wants you to drive the amp on just the "R" input when bridged. When I did this I realized that one of the pair of sub cables coming fom the H701 was not active. I was sending a signal to only one side when driving the 500/1. I'm not sure but I think it likes both to have a signal even if splitting a mono signal. This explains why I had to set the input sensitivity to low and not high like the other amps in the system. I figured out that a setting for the H701 was not right and corrected it. Now both sub outputs from the H701 are active.

All that said I did have to swap the Ref500S for a Precision Power PCX280 because it was too powerful for the subs. In fact even with the gain turned nearly all the way down the PP is almost too much.

What I'm going to do now is leave the PP hokked up for a few days and see if I experience the same issue. If not I'll hook the JL back up, now with both L&R RCA's active and see what happens. I honestly don't think it will make a difference and I'll probably have to look into either repairing or replacing the 500/1, but I sure hope it does!

 

[Mirage_Man 10+ year member]

So with the PP amp hooked I have had no issues with the sub cutting out yet. I think I'm going to hook the JL back up today and see what happens.

Has anyone ever had issues with JL amps acting funny when only hooking up the signal cable to one input?