I have a newly installed JL 300/4 amp in my car and after 30 minutes it gets very hot to the touch. After an hour you can only touch it for about 2 seconds and you'll pull back since it is so hot. Here's my setup:
Kenwood kdc-X979 kenwood 6042g eq Hifonics Zeus zx7500 Jl 300/4 4 gauge wiring for each amp from battery to amps in trunk (@ 18 feet each) The Hifonics amp has a 100 amp fuse and the JL is using a 50 amp fuse. On the JL amp I am running 2 front channels with Boston Pro 60's and rear fill with 2 6x9's. The sub amp is running 2X hifonics 12" subs.
I was thinking it may be the 50 amp fuse is too small? I experimented with the sensitivity and it reacted the same regardless of setting.
What is your level/gain/sensitivity set at on 300/4 amp? Make sure it's properly set according to your HU's preout voltage. Normally amps operate from warm to hot. Very rarely will the amp get very hot unless it's set incorrectly or over driven by not meeting the minimum ohm requirement. Just curious, how hot does it get when the amp is just idling?
Depends on the install of the amp, the fins on that amp should have open air whenever possible. Anyway, you shouldn't be overdriving the amp with the impedance load with those speakers, I'd say it's the gain setting like Isaac stated, and guess you're simply overdriving the amplifier. That amp won't draw more than 50 amps, or near it for that matter, but anyway a fuse won't affect how hot an amplifier runs, a fuse will simply burn out when too much current is pulled across it.
If I turn down the sensitivity, will it drop the operating temperature? The sensitivity is turned to 50% rear and 55% front. How many ohms am I at if I am running the front channels through the PRO 60 boston crossovers? There is one crossover on each of the front channels and the output is to one tweeter and mid for each side. The rear channel is running 2 6x9's (2 way). I have the crossover setting off on the fronts and have run the rear on low pass and off. The rear are currently set to low pass. I have the input set to high voltage on front and rear inputs. My Head unit puts out 5V on the pre-outs. I run those to my EQ and the EQ outs to the amps. I am going out to my car right now to let the amp "idle" to see if it still gets hot. Does the orientation of the amp have a big to do with the temp? I have it mounted against the rear trunk wall vertically with the crossover section and inputs mounted up. The amp also has lights that are supposed to come on for temp and ohm load. Neither of these lights have ever come on. I'll give you guys an update on the amp at idle in about an hour.
On your JL 300/4 amp, what is the input voltage switch set at? Is it on "low" or "high"? Since you mentioned your HU is 5v, that switch should be on "high" and set properly for 5v. Most people mount the amps on the back seat in the trunk so that can't be the problem.
It's on High input voltage front and rear channels. I just went out to check the idle state and that baby is just as hot as when I crank it up for an hour. I had to pull my hand off after 2 seconds. My Hifonics amp is ok, just slightly warm to the touch. My JL amp feels super hot, yet the "thermal" light has not come on? What gives?
Now, I unplugged the rear channel RCA's and turned down the sensitivity all the way to 0 on both channels and switched it to 2ch instead of 4 channel. Let's see if it cools at all.
Sounds like you have a bad amp. It should be cool to warm in idle mode. Only the $hitty Sony runs hot in idle. There could be a problem with the thermal sensor in the amp. JL are suppose to be high quality, but like all electronics, there is no such thing as 100% guarantee.
Great! I just bought it brand new from a guy on Ebay. It was all sealed and obviously new. No warranty from JL however. I have a feeling it might have been somehow damaged in shipping. What to do now? It sound great and I like this amp.
Ask the guy if he has receipt/proof of purchase. If the product is within the warranty period, JL has to honor it. Call the tech support and tell them that you got the amp as a gift and it needs servicing. They should be able to look up the serial number. As long as the product wasn't stolen, I can't foresee any problem.
Here's the latest for those who are wondering. 1st of all, I'd like to say Thanks to everyone with valuable input on my problem. I took apart the amp just to inspect for any burning on the boards or components. Everything looks good and normal. I gotta tell you. These amps are jampacked! No extra room in there at all. I finally decided to call JL tech support directly. I had told them it is a new amp and hooked up to the exact specs outlined in the manual. Correct cabling, grounds and mounting position , sensitiviy, input voltage etc. and that after 1/2 hour of listening at 50-70% level the amp got very hot and I had to pull my hand off after 2 seconds. He asked if the thermal light ever came on. I responded, "No." He said he has the same amp and it is normal for the 300/4 to run very, very hot to the touch. He then asked if the power cable was hot. (it is not) and said no problem, enjoy the amp. All is good. Does this sound right? I'm in So Cal. by the way (not exactly ice cold in my trunk). Any ideas on how to mount a fan or any device to better cool the amp?
Glad I don't have any JL amp. If you have a thermal temperature measuring device, try it. I'd like to know exactly how hot it's getting. Every amp has a "safe" operatering temperature. So if it's exceeding it, then the tech guy is wrong. If you plan on keeping the amp for good, then you can purchase a whisper quiet cpu fan and install it on the amp. You create your own vent for it. A simple procedure like that could do wonders. I've done some testing with my amp. It went from your situation, to hot enough to warm your hands.
It is normal for the slash series amps to run hotter than others, JLs amps will seem hotter than others simply because of the design. The aluminum they use on the case is thicker and not designed to release the bulk of the heat from the amp as others do, the fins are what release heat in the amplifier and the amp "feels" hotter because the case is designed to retain more heat and transfer it to the fins. Didn't read the 2 seconds remark, I pictured burn your skin off hot . Most amps use the entire footprint of the amp for cooling and spread the temperature over the entire amplifier, JLs do not, that's why your other amps felt cooler than your JL amp. The fins do a huge amount of the cooling and actually cool better than if you had an amp that simply used the case as a heatsink. The internals are much cooler than the outside of the amp indicates. Aside from that, the ambient temperature of a vehicle presents a huge impact on how hot an amplifier feels. Remember the inside of a vehicle can approach 200 degrees with the windows up and the sun beaming down, the amp will be scalding hot to the touch even without turning the amp on all day long.
A good test will be during hot summer. Most of my amps play warm, but it does get hot during dog days. So if yours starts of very hot, you got yourself a heater. JLs are designed well, therefore you never know. Only time will tell. All you need is a Sony amp beside JL in winter, and you won't have to turn on your heater.
Yeah, my Xtant 4180c's heatsink gets hot as hell pretty much regardless of gain even with the forced induction cooling and it still sounds sweet. My 1001dx on the other hand runs cool as a cucumber(class D) no matter how hard I push it and it actually has less sink area. I guess it depends a lot on the amp.
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JL 300/4- What has more effect over temp: input sensitivity or crossover setting/pass filters? I have an infrared temp gauge that I use on my RC cars. Next time I get the amp nice and hot I'll take a reading and let you know.
Isaac, I have the JL 300/4- What has more effect over temp: input sensitivity or crossover setting/pass filters? I have an infrared temp gauge that I use on my RC cars. Next time I get the amp nice and hot I'll take a reading and let you know.