Alarming Crack from panels

[MUTZ57]

Ok, so been listening to my ESL11A's through the Musical Fidelity and had swapped out the power amp section to try the Quad 909 power amp and was quite impressed, This configuration was using the pre-out from the Musical Fidelity into the Quad 909 and headed by a Linn Klimax streamer.

As the Linn streamer has a digital volume control I decided to try using the streamer straight into the Quad 909 as a direct connection from the streamer was my previous preference with an improvement in SQ.

I connected everything up and switched on, unfortunately for some reason I was only getting sound out of the left speaker panel, the right panel was mute although the bass was working.


looking at the back of the right speaker the status light was flashing red, so reading the manual it suggests unplugging and re connecting but if the problem persists contact an ML service centre.

Music was playing fine from the left hand channel and the right bass unit just nothing from the panel.

I switched off the Quad 909 from the power switch and got a titanic crack across both speakers such that I thought I had shredded them, I have never heard the like of this and couldn't bring myself to even look at them for a few minutes thinking the worst.

I unplugged the speakers and removed the Quad, disabled the volume control on the streamer and reverted to the Musical fidelity set up to see what would happen.

On powering up the speakers status immediately switched green and joy of joys music was playing again, I sat and listened expecting some issue or other, distortion perhaps or a problem with the panels but thankfully all seems to be ok.

I will continue to convince myself that the event has damaged the panels albeit I can't detect any problems.

Has anyone else experienced this and could give some assurance that the panels are able to withstand such an event, I am assuming it was the panels discharging but in no way would I want to have a repeat of this as it has taken about 5 years off me!!

Any advice would be appreciated as I don't really know what happened and why, I should put the Quad 909 back in via the Musical Fidelity Pre-amp as this set up worked fine but I am reluctant to do so until I can understand what the issue is, I have tried the 909 and streamer direct into a pair of sacrificial Wharfdale Diamonds I keep for trying out gear in case of a fault that main damage my main set up and all appears to be working fine so I am at a loss to understand what the problem is.

The 11A's have been on ever since and are performing as previous so no apparent issues other than the nagging doubt that some damage has been done!

Hopefully someone with more knowledge of these speakers may be able to put my mind at rest.

Thanks in advance for any help!

 

[ttocs]

This is disconcerting indeed. The fact that the "crack" occurred in both channels would lead me to suspect something amp related. If I may theorize without evidence, this crack may possibly be a discharge of power. If so, maybe this would normally be discharging to ground?? into the electric outlet??

Bottom line, I suspect a loose connection somewhere and the lead suspect is the electric outlet, and/or loose power cord.

 

[zigman]

First, don’t stress too much about it! ML has the best customer service I have seen from any company. Even if something went wrong they will troubleshoot and send you the right part to fix. All the electronics are one tray on the base the speaker so super easy for them to help you fix. Very simple with the newer MLs since all the electronics are on a tray at the base of the speaker.

Do you think the cables may have gotten loose from the amp, speaker, or interconnects not fully inserted (or have connection issues)? If you are worried about damage, if your preamp supports balance controls, try to playing one speaker at a time while playing different types of music. The other way is just unplug one speaker at time. I find rock and vocals audibly bring out distortion if it exists. If they sound the same and with no distortion you should be fine. I had a similar thing happen to me on my 11As and one of the panels was obviously distorted.

Agree with ttocs that the sound was probably amp related. Something may have been up with the electronics, maybe because of the amp, and reboot may have just reset it.

 

[MickyP]

Not sure the 909s have a decent protection circuit. I had a mono pair and whenever I turned them on the woofers gave an embarrassing 'thump'. At high levels, too, they seem to lose it a bit. My thoughts, so apols if not aligned with yours. Weirdly I'm using MF stuff now and it's pretty stable.

* Edit to say. I don't think they have any protection circuit!