Question about Jensen JHT525 System
When I turn the sub on it makes this loud humming like noise, all other speakers work fine, I opened the sub up and everything seems fine, nothing blown, any ideas?
If it is a powered sub you should lift the ground. you can do this by adding a three prong to two prong adapter. you know, like when you go to plug something in and the cord your plugging in has three prongs and the outlet your plugging in to only has two. it doesn't have the hole for the ground so you go get a little grey adapter that has three holes on one side and two prongs or tabs on the other.if that doesn't take the hum out (actually, is keeping the hum from getting in) you have a problem with the amplifier.
Posted on Jan 27, 2007
Hopfully you fixed your problem by now but just in case, in addition to what dannydan suggested you may also want to make sure you don't have a ground loop from the ac supply line(120VAC), try relocating the plug to a sepearte outlet on a seperate circuit if possible, or ensure your input cables are not runing next to some ac lines. The hum is usally caused by the EMI (Electromagnet Interference) from your ac lines. this is the 60 cycle hum we get from the 120 Volts 60 Hz lines.
Posted on Jan 19, 2007
I had the same problem with the relevant subwoofer. The problem could simply be about the placement of the rest of the speakers connected to your amplifier. You have to be able to place your fronts and rears in a position that doesn't cause any coincidence. The best placement for a 5.1 system is that fronts are towards you with the subwoofer in between, or next to the front-left, and the rears are just next to your seat. If you use a 2.1 (stereo with a subwoofer), it needs some fine-tuning on the subwoofer and the amplifier as well. I hardly stopped that irritating noise. Firstly, I set the frequency of the subwoofer to 100Hz; then turned the volume down to the quarter level. After all those, I turned up my amplifier's "subwoofer volume leveler" to maximum. I solved the problem. try it out..
Posted on Apr 15, 2007
You could either be using poor quality input cables or they may be damaged and hence pick up interference. I suggest you check your input cables for damage. Use shielded cables from your source to your subwoofer. Your cables might be picking up this interference and transmitting them to the subwoofer amp. This interference can be caused by other equipment (tvs, radios etc) emitting electromagnetic radiotionand Because the subwoofer has its own amp/powered (I hope I'm right in your case), the input cable might be picking up this interference and sending them to the amp alongside the music signal. The amp then does what it knows best:- amplify the input signal. Which in this case is full of interference. Hence the humming. Use good quality shielded cables.
Posted on Nov 12, 2006
I have a Mission Sub-Woofer on my home cinema receiver that suddenly started producing a 'fax' like hum/screech. It has a two core power cable. Replaced the speaker feed cable to no avail. Moved it to another power outlet, same problem. Then noticed it starts exactly on 45 seconds from power up. even with no input cable attached.
I've dropped it into a local AV repair shop to see if they can check the Amp circuit for a dodgy capacitor or something..
Edit: They found a problem in the internal power supply unit circuit. They replaced the PSU, and it's been working perfectly since then.
Posted on Jul 24, 2012
Hopefully your cables aren't damaged, because they're attached to the unit and very difficult to replace. I just had this same problem, and after reading the first suggestion checked my cables for damage and found nothing. However, a closer look at the back of my computer showed that the audio cable running between my sound card and my amp was only halfway in. After correcting the problem, the feedback disappeared. Good luck.
Posted on May 02, 2007
Gtyler in Solution 7 above is probably most correct. AC power often isn't picture perfect and signal conditioning isn't practical at home. When a powered Home Sub signal is amplified, sometimes the noise of fluxuating AC feed is picked up by the amplifier and sent to the speaker as a pop or a crackle.
Solution: If you know what you are doing, condition the DC signal between the converter and the amplifier with an EMI Capacitor. It will cost about $2.50 to fix the whole problem.
Posted on Aug 26, 2008
I work for Cerwin Vega and normally when this happens is ground looping problems, for the solution we would suggest our customers to purchase an adapter from a three prong to a two prong.
Posted on Jan 15, 2008
I had same problem caused by a poorly grounded cable TV line. Try disconnecting the coax cable (the one which comes in from outside) from the back of your cable TV converter box. If the problem goes away, you probably have poorly grounded cable TV service. A $50 ground isolater filter will fix this (see model Model VRD-1FF at: http://www.jensen-transformers.com/iso_vid.html) I installed one recently and it works as promised... No degradation to digital cable/data service and the annoying hum is gone.
Posted on Aug 29, 2007
It also depends on where you have placed the base unit - if it is too close to the amplifier or other electrical devices, this will cause humming. Try moving it atleast a couple of feet away from any electrical devices.
Posted on Jan 01, 2007
I have the same problem. My guess is that the subwoofer coil is messed up. You MIGHT have to get it recoiled. But before you do any of that get someone with a sub to play their sub in your car, if it works.... then your sub is messed up, if not.....then your amp is messed up ( trial and error ). Today i noticed my subs rubber surrounding is crooked, that may be the problem for me. Also when I press down on the sub it makes a sticking sound, like something came loose. So once i get everything opened and out ill let you all know the solution. Good Luck!
Posted on Apr 10, 2008
all the spx17 will do that, no it should not damage the driver.
We usually suggest to customers that it is best to leave the Sub in the Auto switch position as this will allow it to automatically switch on and off without the loud pop.
Posted on Nov 14, 2010
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