Ghost in my Sub?

[Skiman]

Hi all,

Hope someone can help me with a strange problem. Watched 2012 BR last night and all was well with my system and the sub

got a reasonable work-out.

At 05:36 this morning we thought it had all come true albeit some 19 months earlier ( not ultea reliable those old Mayan calendars)

because the whole house (and possibly street) were awakened by the most tremendous rumbling and crashing ( like a rockfall) and

vibrations through the house - as we live 2 miles from Buncefield we thought not again!! But no it was the sub woofer causing the

disturbance but how? - no source switched on and everything on standby.

Unplugged the whole system and went back to bed and when re-emerging into daylight switched everything back on the same thing

happpened intermittently.

Anyone got any ideas? The system is approx. 2 years old and functioned seamlessly in that time up to now.

I can only think it's mains related and strangely enough it first played up at about the same time that the central heating switched on

- coincidence?? Also this morning the broadband had to be rebooted.

Any thoughts would be much appreciated.

Stefan.

 

[Anonymous]

wow, lucky it was'nt paranormal activity you watched last night

that would of spooked ya

 

[kevinJ]

Just wondering, is the sub humming when the receiver is switched on or off?
My sub humms when the sub is turned on and the receiver isn't, so maybe your's is too.

 

[Skiman]

Hi there KevinJ

There is no hum (never has been) from the sub but Ihave just unplugged the beast and

plugged into a seperate socket with and without the rca cable attatched and it's still

making random noises despite changing the position of phase switch although the

intensity of the sounds does alter when changing the phase switch. Looking to me like

an internal problem. Any thoughts anyone?

Regards

Stefan

Stefan

 

[Skiman]

Hi again

Just changed the power lead for a Merlin Black Widow from the original - no difference.

Methinks this is going to get expensive!!!!

Cheers

Stefan

 

[cheyworth]

How old is the sub?

 

[Skiman]

Hi Cheyworth

The sub is just over 2 years old (purchased April 2008) and came as a package deal with the surrounds, centre and AV

amp.

Cheers

Stefan

 

[f1only]

Hi, i had a similar thing with my Sub a few years ago & upon opening the unit i found it had a dry solder joint giving it feedback.

If you can open it up easily, & check all the solder joints it might help solve the problem.

Hope that helps.. regards

 

[Skiman]

Hi f1only, thanks for the reply. I've now altered the AV amp settings to SUB OFF to eliminate any output connection problems and the problem persists so it does appear to be an intenal sub problem.

Regarding your suggestion it does indeed sound logical. Can this sort of thing just happen instantaneously? Would I have to power down the sub for 48 hours to allow any residual current to dissapate? Is there any tell tale signs to look for to identify a dry joint? Any info would be greatly appreciated.

Regards

Stefan

 

[chudleighpaul]

Sounds to me as if the auto standby is not working. If your amp has switched AC out, try powering the sub from that. When you switch off the amp, the sub will be switched off, so it should be impossible for sub to emit any sound at all

 

[f1only]

I would try chudleighpauls suggestion 1st. When mine did it i unplugged from the mains left it 1/2 hour & went around all the solder joins inside with a soldering iron & if any looked like they had bad joins ( dull looking solder or loose connection ) i just refreshed it with new solder.

Mine happened like yours by the sound of it. I went to bed one night & about 3am all i could hear was this constant rumble, my amp was switched off but the noise was still there. The auto shut off had appeared not to have worked & turned the Sub back on but with this horrid noise. Next day i turned everything back on & all was the same, with the amp on or off.

As far as i am aware though not to much inside that has major residual voltages or amps, easiest way to get rid of though is plug it in turn it on then unplug from the wall, leave it turned on ( UNPLUGGED FROM THE MAINS ) which should eat up anything left, over 1/2 hour period just to be on the safe side.

Hope that helps ... Regards ... Paul

 

[Skiman]

Hi all, thanks for the responses to my problem. A quick update for those who are interested - spoke to the suppliers (Creative Audio)

in Shrewsbury who diagnosed a failed pre-amp due to naughty me leaving the sub in stand-by mode. As the unit is 8 weeks out of

warranty the company has offered to replace the failed component with a modified unit for approx. £40.00 plus any carriage (will

probably do delivery and collection myself as I am lucky enough to have company car and fuel).

I think they have been very reasonable and there was no hesitation in offering me the reduced repair costs - in fact they said if I can

get it there tomorrow I can have it back by the weekend.

All in all I'm a much relieved bunny.

As usual thanks to the contributors on this forum who have always had a helping hand to offer.

Regards

Stefan