JBL PRX6-15m and JBL PRX618S-XLF Overheating Solution

I currently have (2)JBL PRX6-15m & (2) JBL PRX618S-XLF speakers as part of my DJ System.
Date: 3/22/2012

I had the grey JBL EONS G1s for 8 years which led to buy the new PRX6 series. I bought my new speakers on 1/12/2011 so after reading the forums I think I have the first generation speakers for the series.

Issue:

My first overheating experience was at a small bar/club and my console, two tops and one 18in subs were in the corner. After 3 hours my sub turn off 2 times due to amp getting hot. The next day I called JBL about my problem and they said the speakers needed more air circulation or else it will shutdown otherwise you need to get a small 5in house fan. I then hung up. Wow, If they only spent $5 on a installing an internal fan like QSC I would have this problem! DOH!

My second experience with overheating was at a wedding. I had my two 15in top and after 3 hours in to the dance I notice the speakers sounding weird. They did not shutdown but I was pushing them enough for the red limiter to come with every bass note. The amp was hot and it sounded like the circuitry was toning down the bass for me which kept me pushing up the volume on the mixer (this was before I noticed the red limiter). Soon it started sounding like a large old school boom box. After that the mid range got crappy from all the distortion and I finally brought the volume half way down.

Thoughts:

The speakers sound awesome for the first couple hours when the amp is not super hot, after that it all goes to pot. The amps seem to live on the edge of meltdown due to it having no fan or any type of circulation, not even holes to let air pass through the inside of the amp where are the components live. An almost flat heat sink is just not enough to cool the amp sufficiently. I wish they did some real world testing before they mass produce it. Imagine if this was an outdoor party during a hot day; overheat in 30 minutes = Epic Fail.

Solution:

Here is what I had to do to resolve my PRX6-15m & PRX618S-XLF overheating issue.

I went to "TAPs Plastic" (A store that sell raw plastic sheets) and bought a 1/4in Black 9inx9in sheet of ABS Plastic.
I put it in the oven (wife not around) for 15-20 minutes at 325 degrees to soften the plastic so it can be molded.

 

Made a crude Form out 2x4in wood.

 

After 12-20 minutes I pulled the plastic out (very hot) and placed on the form.
Using scrap wood on top, I pressed the plastic in to the form using my body weight.

 

Close up of bent plastic.

 

Close up of plastic with out wood on top.

 

Close up for new plastic form.  Yes, that's a big jar of rice in the back.

 

Two forms made. Cool down for 30 minutes.

 

Using a drill and dremal with a drill type bit I cut out the holes.
I mounted a fan, IEC plug and two power outlet plugs to make a mini power strip.
I bought the parts from a local electronics shop. Fry's electronics has this stuff too.

 

Underside. Yes I did cover insulate the wires and cover the power supply with its original plastic housing before mounting the plate. Power supply is screw the black plate and not doubled tape.
I used a 12volt fan with a 9volt power supply.
A 12volt power supply made the fan too loud and I wanted to slow the fan speed down a little.
The power plug wire that powers the speaker is not shown in this picture.

 

 

I bought four 5mm x 20mm screws from Home depot and mounted the plate.
Original screws are 5mm x 12mm.
Fabric speaker covers still fit over the speakers.

I unplug the power cord and let it dangle when in storage or I can tuck the wire under the plate. The wire does not reach the ground. I didn't use a right angle IEC power plug because what I had was 18guage wire (thin, from a regular computer) so I use a 14 gauge (thick) power cord used on a copmuter servers, plus it was free.

Conclusion:

I made four fan plates for my speakers and I have not had an issue since installing them.

I have used all four speakers at full volume for 4 hours straight and the amp plate is always luke warm when I checked every 30 minutes. Pictures on right is a gig where I tested the new fans on the speakers.

The sound quality is excellent from start to end of the event like how it should be.