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Outnumbered
08-09-2005, 08:06 PM
I posted this in the A/V section too but was looking for a quick answer:
I have an unknown model Fosgate that keeps shutting down. I think its from heat because it is in a poorly ventilated area. Could also be possible that it is low voltage. I have a JL 500/1 in the same mounting area that has never shut down. I was thinking of taking out the Fosgate and replacing it with a JL 450/4. Does this sound like a good idea or should I keep the Fosgate and get a fan? The Fosgate is running 4 JL 6.5s on the rear and 2 Infinity Kappa 6x9s on the fronts.
Here are pics of the Fosgate. Does anyone know what model it is?
Thanks
http://www2.***boat.com/image_center/data/500/973P8080070.JPG http://www2.***boat.com/image_center/data/500/973P8080069.JPG

jbone
08-09-2005, 08:42 PM
I'm no audio expert, but I have the Punch 4004 pushing 4 Infinity Kappa 6x9's and a Punch 5002 bridged pushing one 12" Fosgate sub.
I have the amps under the rear bench seat. There is NO ventilation at all and I push it to full capacity for hours in extreme heat (116) 3 weeks ago. Neither amp has ever shut down due to overheating.
I mounted the amps about an inch off the floor though. This may help in cooling.
J

KACHINA KEN
08-09-2005, 08:45 PM
How are they wired? What ohm load are you bringing it down to?

jbone
08-09-2005, 08:51 PM
I went to the Fosgate website and it looks like that was a Power series amp.
Check this link.
http://www.rockfordfosgate.com/ez2/ModelInfo/ModelInfo.asp?ItemKey=10061239&CategoryDesc=Power%20Amplifiers
You mentioned JL Audio. If your gonna replace your amp, you can't go wrong with JL.
J

Outnumbered
08-09-2005, 08:58 PM
How are they wired? What ohm load are you bringing it down to?
4ohms on the fronts and 2 ohms on the rears. Its a 4-channel amp.

Outnumbered
08-09-2005, 09:03 PM
I went to the Fosgate website and it looks like that was a Power series amp.
Check this link.
http://www.rockfordfosgate.com/ez2/ModelInfo/ModelInfo.asp?ItemKey=10061239&CategoryDesc=Power%20Amplifiers
You mentioned JL Audio. If your gonna replace your amp, you can't go wrong with JL.
J
That is a sub amp. This is a 4-channel and it does not look like any of the 4-channels on their site. I think its about 3 years old based on what I can gather from the original owner so I doubt it will be in their current line-up.

Havasu Hangin'
08-09-2005, 09:04 PM
You need to move some air over those Rockford Hotplates...

KACHINA KEN
08-09-2005, 09:09 PM
4ohms on the fronts and 2 ohms on the rears. Its a 4-channel amp.
Have you tried running/ wiring it all uniform either 2 or 4 ohm? What is the amp rated at ?

jbone
08-09-2005, 09:10 PM
How about this one then.
http://www.rockfordfosgate.com/ez2/ModelInfo/ModelInfo.asp?ItemKey=10061237&CategoryDesc=Power%20Amplifiers
If you go on their site and click on Amplifiers, then click on compare, you will find a list of amps made over the past few years. This amp was made in 2003.
Their are a few 4 channel amps. I think this one is 70 watts per channel.
J

Outnumbered
08-09-2005, 09:10 PM
You need to move some air over those Rockford Hotplates...
Ya, that focker cooks in there. I just was trying to avoid running a fan because of the additional drain on the batteries. The JL is cool enough to rest your hand on, the RF will brand your skin.

Outnumbered
08-09-2005, 09:13 PM
How about this one then.
http://www.rockfordfosgate.com/ez2/ModelInfo/ModelInfo.asp?ItemKey=10061237&CategoryDesc=Power%20Amplifiers
If you go on their site and click on Amplifiers, then click on compare, you will find a list of amps made over the past few years. This amp was made in 2003.
Their are a few 4 channel amps. I think this one is 70 watts per channel.
J
I saw that one, its close. It looks like it has end caps on it. It is a smaller amp though if you count the fins, mine is quite a bit bigger. Thanks for the tip though, were getting closer.

Outnumbered
08-09-2005, 09:14 PM
Have you tried running/ wiring it all uniform either 2 or 4 ohm? What is the amp rated at ?
Should not matter as all Fosgates are stable down to 2 ohm load.

Teabagger
08-09-2005, 09:19 PM
Does it only cut out only when playing loud? If so, you are likely running those 4 rear speakers in parallel which means you are likely running a 2ohm or lower load. This is hard to do for many amps (eapecially multi channel stereo amps, not sub amps).
You shoud run them in a combination serial/parallel or even straight serial configuration to make less of a load on the amp.
Here is a good website to learn more:
http://www.bcae1.com/spkrmlti.htm

Outnumbered
08-09-2005, 09:20 PM
Jbone, thanks for the help. I think I found it. If you count the fins it matches and it is also the same colors. Mine is just missing the cable-cover end caps:
http://www.rockfordfosgate.com/ez2/ModelInfo/ModelInfo.asp?ItemKey=10061230&CategoryDesc=Punch%20Amplifiers
http://www.rockfordfosgate.com/ez2/fcsscripts/Images/Rockford/2003/Amplifiers/PUNCH801_F.jpg

jbone
08-09-2005, 09:21 PM
This one?
http://www.rockfordfosgate.com/ez2/ModelInfo/ModelInfo.asp?ItemKey=10061238&CategoryDesc=Power%20Amplifiers
Same amount of fins. 4 channels. Yours had end caps at one time. Someone decided to keep them off. You have the single screw that held each cap in place still in the hole.
You are right though. My amps will seriously burn you if you touch them after crankin for a while.
J

Outnumbered
08-09-2005, 09:25 PM
This one?
http://www.rockfordfosgate.com/ez2/ModelInfo/ModelInfo.asp?ItemKey=10061238&CategoryDesc=Power%20Amplifiers
Same amount of fins. 4 channels. Yours had end caps at one time. Someone decided to keep them off. You have the single screw that held each cap in place still in the hole.
You are right though. My amps will seriously burn you if you touch them after crankin for a while.
J
No, I think its the 801 not the 851 because the 801 is red and the 851 is blue.

Outnumbered
08-09-2005, 09:27 PM
OK, now that we know what I have, should I replace it with a JL 450/4 or put a fan on what I have? The JL has a lower power output but it may sound better. :confused:

Outnumbered
08-09-2005, 09:30 PM
Does it only cut out only when playing loud? If so, you are likely running those 4 rear speakers in parallel which means you are likely running a 2ohm or lower load. This is hard to do for many amps (eapecially multi channel stereo amps, not sub amps).
You shoud run them in a combination serial/parallel or even straight serial configuration to make less of a load on the amp.
Here is a good website to learn more:
http://www.bcae1.com/spkrmlti.htm
Yes, it shuts down after about an hour of loud play. Usually recovers in about 10 minutes.
I'm pretty sure they are wired parallel which, according to RF, is OK. The amp is rated to 2 ohms and puts out 200watts per channel at that load.

Teabagger
08-09-2005, 09:35 PM
Hmm, sounds to me it's too much of a load on the amp thus it getting way hot. RF amps already run hot but I'm willing to bet that at the volumes you are playing at, it's too much for the amp to handle so it overheats and goes into protection mode. It never does turns off at lower levels right?
Your only options are to either re-wire the speakers or buy a new more stable amp. I'd try the speaker wiring first as it's free and should be relatively easy to do. If you got the money to spend, simply replace the amp, it might be less of a headache in the long run.

jbone
08-09-2005, 09:36 PM
I would go with JL Audio on every amp I buy, but the money comes into play. If you already had one, it would be nice to match.
You said your JL does not get hot, my Fosgates get extremely hot, but don't shut down. I've been impressed with they offer for the $$$. But if I had the extra $$$ I'd get the JL without a doubt.
J

Outnumbered
08-09-2005, 09:37 PM
Hmm, sounds to me it's too much of a load on the amp thus it getting way hot. RF amps already run hot but I'm willing to bet that at the volumes you are playing at, it's too much for the amp to handle so it overheats and goes into protection mode. It never does turns off at lower levels right?
Your only options are to either re-wire the speakers or buy a new more stable amp. I'd try the speaker wiring first as it's free and should be relatively easy to do. If you got the money to spend, simply replace the amp, it might be less of a headache in the long run.
What amp would you recommend? I have had good luck with the JL stuff but don't want to step down in power if it will be noticable. The sub amp is JL now so they would match.

jbone
08-09-2005, 09:46 PM
I think the one you mentioned 450/4 is a great choice.
What do you think about your Kappa 6x9's? I've been happy with mine.
J

Outnumbered
08-09-2005, 09:59 PM
I think the one you mentioned 450/4 is a great choice.
What do you think about your Kappa 6x9's? I've been happy with mine.
J
I'm not sure. They are mounted in a shitty place so its hard to compare. They are in the bow seat risers, near the floor, facing each other about 18" apart. I got the marine version because the JL 6.5s that were there before were wasted from getting kicked and the grills rusted from water. I guess for their location they sound fine.

KACHINA KEN
08-09-2005, 10:14 PM
Should not matter as all Fosgates are stable down to 2 ohm load.
Yeah but what I'm wondering is if it needs to be uniform all the way across or if it creates a problem form being ohm imbalanced. It's worth checking out

Beer-30
08-09-2005, 10:22 PM
You could either add one more battery and run as many fans as you want off of it. Or, just run the fans off of the starter battery. It is a bit more risky doing it that way, but it would take a month of Sundays for a fan or two to run a battery down. :sqeyes:

'78 gt boat
08-09-2005, 10:25 PM
I would think based on what you are running 6 speakers off of a four channel amp. Two channels for the pair of 6x9's and 4 6.5's on the other two channels. Are you running the 4 6.5's mono or stereo. It sounds like the amp is pushing more wattage than it can handle therefore it overheats and shuts down for a while. My wife has a BD1000 running her two Alpine DVC subs and a 4 channel very similar to yours running one set of Boston pro 6.5 coax and a pair of Boston Pro 6.5" components in her SUV and it pounds all day long with no shutting off. Fosgate amps do run hot. Nothin wrong with JL amps and not a problem having a matching pair. Try diconnecting one pair of the 6.5's and run it to see if it shuts off or not. This should tell you if you are overloading the amp or not. Or you can run a test with a meter to see what ohm load the amp is seeing. Just my .02

Outnumbered
08-09-2005, 10:44 PM
I would think based on what you are running 6 speakers off of a four channel amp. Two channels for the pair of 6x9's and 4 6.5's on the other two channels. Are you running the 4 6.5's mono or stereo. It sounds like the amp is pushing more wattage than it can handle therefore it overheats and shuts down for a while. My wife has a BD1000 running her two Alpine DVC subs and a 4 channel very similar to yours running one set of Boston pro 6.5 coax and a pair of Boston Pro 6.5" components in her SUV and it pounds all day long with no shutting off. Fosgate amps do run hot. Nothin wrong with JL amps and not a problem having a matching pair. Try diconnecting one pair of the 6.5's and run it to see if it shuts off or not. This should tell you if you are overloading the amp or not. Or you can run a test with a meter to see what ohm load the amp is seeing. Just my .02
Accordning to Fosgate, its not running more than it can handle. Its within spec. The amp is designed to run down to 2ohms. Two 4ohm speakers on each chanel will drop the ohms to 2ohms per channel and that puts out 200W on each rear channel. The fronts are at 4ohms at 100W for a total of 600 W.
The lower ohm load will create more heat, which is my suspicion of the cause--the heat. I'm just wondering if the JL would be any better as far as running cooler.

Havasu Hangin'
08-10-2005, 03:49 AM
Ya, that focker cooks in there. I just was trying to avoid running a fan because of the additional drain on the batteries. The JL is cool enough to rest your hand on, the RF will brand your skin.
Cooling fans have a minimal amp draw. My old ones only drew 1/4 of an amp each (compared to the system which drew over 150 amps at full tilt).
I have always had struggles keeping RF amplifiers cool in a boat in the desert heat. They run so hot, if they are in a closed space, you gotta get air in, over them, then out, which is not always easy.
Since your JL is a class D, it will never get hot. If you went with a JL class a/b will also get hot, if not ventilated (just not as quickly as the RF).

Outnumbered
08-10-2005, 07:49 AM
Cooling fans have a minimal amp draw. My old ones only drew 1/4 of an amp each (compared to the system which drew over 150 amps at full tilt).
I have always had struggles keeping RF amplifiers cool in a boat in the desert heat. They run so hot, if they are in a closed space, you gotta get air in, over them, then out, which is not always easy.
Since your JL is a class D, it will never get hot. If you went with a JL class a/b will also get hot, if not ventilated (just not as quickly as the RF).
I'm not sure if the 450/4 is a class D. Am I taking a step back going from a Fosgate to a lower power JL?

sigepmock
08-10-2005, 08:05 AM
THe 450/4 is a class a/b, only the sub amps are digital or class D and then only the good ones. I run a JL E650 in the boat, it's a 6 channel amp. I run 4 JL6.5's off 2 channels, 2 JL6x9's off two channels and the last two channels feed two MB Quart 6x9's in under the hatch boxes. I have switched everything ove to JL they do not run nearly as hot as the RF. The RF always shut down, I tried fans, Hell I would even soak a small towel in the water and set it on the amp to cool it down. Since switching to the JL's, they have NEVER shut down once. On the new boat the amp is behind the side panel, buried very deep with little or no air flow and it never over heats, the two batteries die before amp shuts down. Maybe it's just luck but I will never run RF amps for my mids and high's again, maybe one of their BD sub amps.
Any way switch to the JL 450/4 or try the new E650M(6 channel) Marine amp and run a channel to each set of speakers(bridged it puts out 150 watts RMS to 3 channels at 4 ohms) :D I think you'll be much happier not having to worry about the amps anymore.
Just my $.02,
Chris

jstwkd
08-10-2005, 08:53 AM
If your running down to 2 ohms with low V+ then the amp will shut down.What is the Batt V+ when the amp drops off?Is the boat running or off?What size alt are you running?If your running a 2ohm l;oad you should be running a batt for each amp...what type of batt are you running?WHat is the amp hrs on the batt..
I get about an hr out of mine at full volume....I run a class D sub amp with fans and its own battery @ 1 ohm pushing 2 12in subs @1400 watts.And another amp with fans on its own battery running 6-6.5 seporates...@ 2 ohms-1000 watts.ounce the batt V+ dropps below a certain voltage the amp goes into protective mode...and shuts down....I run another battery for the rest of the boat....

Outnumbered
08-10-2005, 09:02 AM
THe 450/4 is a class a/b, only the sub amps are digital or class D and then only the good ones. I run a JL E650 in the boat, it's a 6 channel amp. I run 4 JL6.5's off 2 channels, 2 JL6x9's off two channels and the last two channels feed two MB Quart 6x9's in under the hatch boxes. I have switched everything ove to JL they do not run nearly as hot as the RF. The RF always shut down, I tried fans, Hell I would even soak a small towel in the water and set it on the amp to cool it down. Since switching to the JL's, they have NEVER shut down once. On the new boat the amp is behind the side panel, buried very deep with little or no air flow and it never over heats, the two batteries die before amp shuts down. Maybe it's just luck but I will never run RF amps for my mids and high's again, maybe one of their BD sub amps.
Any way switch to the JL 450/4 or try the new E650M(6 channel) Marine amp and run a channel to each set of speakers(bridged it puts out 150 watts RMS to 3 channels at 4 ohms) :D I think you'll be much happier not having to worry about the amps anymore.
Just my $.02,
Chris
Cool, thanks for the info. I like the idea of the 6 channel set-up. I'm going to look into this.

sigepmock
08-10-2005, 10:20 AM
Roz used to be the hook-up on JL amps but I think he gave that up. I know Parker (Dave from Al & Ed's in Ontario) can help you out too. He really took care of me on the latest truck upgrades.
Wkd is correct about the voltage but like I said, since I switched to JL's I haven't even had to worry about the amp anymore. Good luck and let me know if you need Dave's number.
Chris