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MFW-15 strange noise

post #1 of 7
9/26/11 at 5:57am
Thread Starter 
Hello everyone! I am new to the forum, and pretty new to home theatre sound, so I apologize up front if I am not very technical in descriptions.

A few years ago I purchased a MFW-15 from av123. I bought the updated version with the new amp which corrected prior issues. Within the last several months when I plug in the sub and click on the power switch, a strange "fuzz" noise will pulse three or four times and then stop. The sound does not happen again when left on and the sub runs great during use. This sound only happens when the sub is turned on and never lasts more than a few seconds. Any idea what is going on? Should this be a concern??

Just to check things out I removed the amp from the back of the sub and everything seemed in order (to my untrained eye) and nothing was loose. The only thing I noticed was a wire going from the amp into the speaker enclosure was extremely long and most of it was in the enclosure not in the smaller compartment where the amp is mounted. Could the extra length of wire be resting the on the cone??

Again I apologize for my lack of technical terms here but I am learning and this issue is all new to me.

Thanks for the help.
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post #2 of 7
9/26/11 at 2:07pm
I suppose it's possible that the long wire is interfering with the driver. More likely (even though you have an amp that allegedly fixed prior issues) is the amp might be ready to "blow their caps".

In short, the v2 amps were not any better than the v1 amps (except the very early versions of v1). There is also a v3 of the amp. Do a search for an AVS member called "murrel" of Simply Sound Audio.

While I don't have one of his amps, he had contracted to have a solid amp for the MFW 15. From everything I've read (it's been awhile since I've visited any MFW 15 forums), it's supposed to be rock solid.

I would go the path of least resistance first and make certain that the "stray" wire isn't the cause. Then, I'd play the MFW until (I would say "if", but the odds of it failing are pretty high) it gives up the ghost and then contact "murrel".

Best of luck!
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post #3 of 7
9/26/11 at 2:12pm
Here is the "master" MFW problem and solution thread Johnny.

http://www.avsforum.com/avs-vb/showthread.php?t=1250559


Start towards the rear
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post #4 of 7
9/26/11 at 3:03pm
Quote:
Originally Posted by johnnymite View Post

Hello everyone! I am new to the forum, and pretty new to home theatre sound, so I apologize up front if I am not very technical in descriptions.

A few years ago I purchased a MFW-15 from av123. I bought the updated version with the new amp which corrected prior issues. Within the last several months when I plug in the sub and click on the power switch, a strange "fuzz" noise will pulse three or four times and then stop. The sound does not happen again when left on and the sub runs great during use. This sound only happens when the sub is turned on and never lasts more than a few seconds. Any idea what is going on? Should this be a concern??

Just to check things out I removed the amp from the back of the sub and everything seemed in order (to my untrained eye) and nothing was loose. The only thing I noticed was a wire going from the amp into the speaker enclosure was extremely long and most of it was in the enclosure not in the smaller compartment where the amp is mounted. Could the extra length of wire be resting the on the cone??

Again I apologize for my lack of technical terms here but I am learning and this issue is all new to me.

Thanks for the help.

Johnny,

You are more than welcome to contact me about your amp. I would be happy to try and help!

Murrel
Simply Sound Audio
simplysound@msn.com
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post #5 of 7
9/27/11 at 5:14am
Thread Starter 
Thanks for the advice and directing me to murrel.

Murrel, I am going to email you directly if that is ok. Thanks for offering to help.
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post #6 of 7
11/16/11 at 8:09am
Hi,

Kudos to Murrel.

I have a MFW15 that worked great till it decided to humm. That humm was with all inputs disconnected. Murrel send me the instructions and BOM. A day later I had everything and fixed it in 5 minutes. Hummm gone.

Till I connected the receiver. Another humm is back.

Murrel determined this was a "ground loop" gratuity of the cable company. Bingo, disconnecting the cable killed the humm. This humm occurs if the sub and the cable have different ground, resulting in humm. Don't ask me how, who cares anyway. The fix suggestion from Murrel took another 5 minutes and now the sub is a silent when plugged, on and connected as it is when unplugged.

I have 3 sets of condensers leftover to fix MFW15s v2. I bought more than I needed, in case I'd fry something.

Again, thanks Murrel, you are not just an expert, but a nice helping hand, always fast to respond. Keep up the good work and good business!

Hans
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post #7 of 7
11/16/11 at 12:55pm
Quote:
Originally Posted by hanskra View Post

Hi,

Kudos to Murrel.

I have a MFW15 that worked great till it decided to humm. That humm was with all inputs disconnected. Murrel send me the instructions and BOM. A day later I had everything and fixed it in 5 minutes. Hummm gone.

Till I connected the receiver. Another humm is back.

Murrel determined this was a "ground loop" gratuity of the cable company. Bingo, disconnecting the cable killed the humm. This humm occurs if the sub and the cable have different ground, resulting in humm. Don't ask me how, who cares anyway. The fix suggestion from Murrel took another 5 minutes and now the sub is a silent when plugged, on and connected as it is when unplugged.

I have 3 sets of condensers leftover to fix MFW15s v2. I bought more than I needed, in case I'd fry something.

Again, thanks Murrel, you are not just an expert, but a nice helping hand, always fast to respond. Keep up the good work and good business!

Hans

Hans,

Glad we got you all fixed.
you are welcome.

Murrel
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