Quest Panel humming !

Hi folks,
I've just joined but have a bit of a query, I have a ML 5.1 setup but have noticed that there is a loud hum coming from one of the Quest speakers' panels.
I am using Mark Levinson 331 amps (bridged) to the front speakers. They are connected via XLRs to a Bryston SP7.1 pre-amp.

I've tried swapping the XLRs to each speaker/amp at the preamp but have found that the problem is definitely with the speaker panel itself - as connecting the other amp to it still makes it hum! The same amp does not hum when connected to the other speaker.

I even tried to unplug the speaker overnight and disconnect it from the power amp but this had no effect.

I did notice that if I took the XLR for the power amp to this speaker off at the preamp side that the hum was MUCH louder. It went quieter as soon as I reconnected the XLR to the preamp again.

I have had the same setup for many months but have never had anything like this before.

Any advice? Is it likely to be a problem with a component in the X over ?

Any help would be much appreciated!

Try exchanging left and right interconnects. Hum is usually a ground problem, and may well be a broken lead in one of the cables.

Just to Add, I believe for a fast answer ...Bernard is "spot-on." Admittedly, there could other answers / solutions.

Humming!

Why don't you contact martin logan and let them help you and you won't have to guess on what to do next? Good luck?

khenegar said:

Why don't you contact martin logan and let them help you and you won't have to guess on what to do next? Good luck?

Click to expand...

Thanks for your help with this everyone. I will send an email to ML. I've tried everything now I think and the hum is still there!

I think I read somewhere in ML literature that the electrostatic speakers might hum if they are too dusty. I think it is the manual that suggests cleaning them out by using compressed air or some other careful method. Just a stab in the dark. You would expect though that both speakers would probably have the same amount of dust.

sphynx said:

I think I read somewhere in ML literature that the electrostatic speakers might hum if they are too dusty. I think it is the manual that suggests cleaning them out by using compressed air or some other careful method. Just a stab in the dark. You would expect though that both speakers would probably have the same amount of dust.

Click to expand...

Sorted. It was one of the three mark levinson 331 power amps. I am using them bridged to power the front quests and the centre Theatre speaker. The buzzing slowly builds up as the amp is switched on - after being switched off for a few days.... I suspect that it could be the capacitors! (?)

Hola. Could be a ground loop. Some amps are more sensible to this, even the same brand and model. And nobody knows why. A quick test. Drive the bad channel with only one channel. Not bridged. If the problem persists, disconnect the cable antenna from the tv or the cable box. No tv will be. Usually this is the culprit, and it is due the potential difference between the ground of the outside post of the house, and the ground of your house. Easy to fix. Just a ground loop suppressor, where you can get it at Rata Shack. Do the test and tell us how you are doing. Happy listening!

Thanks very much for that. I will try this !