madurant short ms206 crackle problem

[admin_exported]

hello.... again. I brought these speakers new about 8 years ago from richer sounds when i found out i was going to have a kid i put my pride and joy in the loft wrapped in plastic so they didnt get TFTS (toddlers finger tweeter syndrome). 6 years later iv decided to get myself a marantz mcr603 for xmas

i connected my still new looking ms206 on the new amp but one of the speakers has a crackle on vocals especialy. Iv swapped the individual speaker from the left housing to the right to make sure its not cable related and its still there

you can feel the coil rubbing inside if you push/pull the cone but i have found that if i put a packer under one of the screws it fine no rubbing and perfect sound

1)any idea why this has happened

2)could it blow my amp if it rubs on the coil at a later date and shorts (think it has a protection circuit)

3) im my head these were super speakers think they had a rrp of £600 before MS went bump are they any good compared to B&W cm1's

4)will my repair last, i was told its called sagging and to rotate the speaker 180 in the housing if so is it a comon fault?

thanks again for any input

oh one last thing although it might need another post in my marantz i cant get web control to work i have the iphone app working but on my pc but when i type the ip address of the unit i just get an option to change the marantz name

 

[Big Chris]

If you can spin the driver 180 degrees and it cures the problem, then great. You've fixed it for free!

 

[Mooly]

1. It may be that the metal frame of the speaker is not rigid enough and the front panel has warped and pulled the cone/coil out of line. I would remove the speaker and examine it. Another slim but real possibility is for a tiny piece of loose metal (such as a burr from a screw etc) to have found its way into the coil/magnet cap. You might be able to see it as it would not enter the gap but sit on the rim where it could catch the coil. If that were so then removal is easy once you know how... a piece of plastic with a bit of sticky tape on the end and just touch it to the metal object.

2. In theory if the top and bottom ends of the coil rubbed and the insulation wore off and if the coil got stuck and if it happened for both ends to be in good electrical contact with the magnet then yes. In reality that won't happen, the amp is safe. Protection circuits very often don't As witnessed by countless failed amps with shorted output transitors. This scenario... I would say safe.

3. No idea

4. I've never heard of rotating a speaker 180 tbh... if the cone sags under its own weight then its a lousy design imo. The magnetic gap in a bass speaker is bigger than you might think.

A really good test for a rubbing (bass only) speaker is to get (or burn your own) a test CD that has a low frequency of around 5hz (must be sine wave) or even lower. A modern DC coupled amp will reproduce that and the cone will move slowly (and absolutely silently) in and out.

 

[bigblue235]

3) im my head these were super speakers think they had a rrp of £600 before MS went bump are they any good compared to B&W cm1's

They're very different from the CM1s. The MS206 were a fairly hefty floorstander, the CM1 are a stand-mounter.

They're certainly worth saving if you can. I think other models in the range were given a 4* review from the mag, but I'm not sure the 206 were as much as £600, that was maybe the 207. I still have a pair of 206, and I think I paid £129 in one of Richer's monthly specials!

Mine might be getting dragged back into action with a little Marantz or something too, as my current gear doesn't fit in with the decor of our new place