M&K MX-350 THX Subwoofer Electric Shock

Getting shocked by your equipment is not normal. I have had a pair of

MX-350's in my HT for about 3 years and have never experienced anything like that despite extensive calibration and testing.


The toggle switches on my 350's have plastic covers over the metal tips, do yours? Also, when did you buy your 350? Did you buy it from and authorized M&K dealer or were they assembled from auctioned parts after M&K was dissolved, i.e. did you buy it from eBay within the last year or so?

I brushed against the outputs on my PA Amp (Approx 3000w~).

Blacked me out for a couple seconds.

I'd get it checked..



Quote:
Originally Posted by Monty Williams /forum/post/14122959


Getting shocked by your equipment is not normal. I have had a pair of

MX-350's in my HT for about 3 years and have never experienced anything like that despite extensive calibration and testing.


The toggle switches on my 350's have plastic covers over the metal tips, do yours? Also, when did you buy your 350? Did you buy it from and authorized M&K dealer or were they assembled from auctioned parts after M&K was dissolved, i.e. did you buy it from eBay within the last year or so?

Click to expand...

Interesting, mine does not have plastic cover over the metallic toggle switches. Could it be that it is necessary? Are you able to temporary remove it and test it with a test pen while the subwoofer is switched on?


This subwoofer is the original purchase from an authorised M&K dealer. They have not come back to me yet but at the mean time just want to find out from other similar users on their experience.


Thanks.

I'll check them tonight, but I'd be very surprised, if not alarmed, if there is voltage across the exterior of the switches.

I would also check your in-wall wiring. Hot/neutral swap, maybe...

You aren't using any ground defeat devices are you? (cutting ground pin, ground lift plug, etc...)


Peter M

Solved!

Managed to check each of them and found two equipment with wrong polarity connection.

Thanks for all your comments...

That series of M&K subs DOES NOT even HAVE a U-ground pin on the power cord. The input winding to the power transformer is completely floating. Therefore you CANNOT get a "ground loop" with that sub.


However, it is possible that something (some component) in the sub, or its power supply, (or somewhere else) has failed, and is producing leakage current to the outside "ground" of the RCA input plug, but typically the problem will be somewhere else, not the sub itself OR its associated AC wiring.


When you say "wrong polarity connection" are you referring to the actual AC outlets themselves bein wired wrong or are you referrin to some UNpolarized AC PLUGS that were inserted the 'other' way?



Barry

I have a client of mine. He used to have an M&K sub. Also used to have a house until the sub burned it down. True story. DEFINITELY have it checked.

^^^^Says the Klipsch dealer.



Quote:
Originally Posted by Monty Williams /forum/post/14212479


^^^^Says the Klipsch dealer.

Click to expand...

Yes, I am a Klipsch dealer. What does that have to do with anything? The fire is a matter of public record. House was located in Semiahmoo area of Blaine WA. The client owns a well known international electronics manufacturing operation. Fire was traced to a defective amp in the sub which caught fire and burned the house to the ground. There was a lawsuit and eventual settlement for a sum which he cannot disclose.