Grotto subwoofer hum.. Not ground loop!

[Mirage_Man]

Hello. I recently purchased a used Grotto subwoofer to use in a bedroom system. Love the sub but it has a hum that is constant. It does not go away when the signal cable is disconnected nor does it go away when I tried a cheater plug. I've read that it could possibly be the transformer humming. Idk but I'm not all that bad with a soldering iron if this a simple fix.

Anyone have any ideas?

 

[Speedskater]

Did you try a shorting plug on the RCA input?

 

[Mirage_Man]

Did you try a shorting plug on the RCA input?

Never heard of one. What is the idea behind it? And would I use them on all the inputs?

As a side note, searching this subject on the net brings up a few instances where people had similar problems with the grotto. Perhaps it's an inherent issue with the amp design or a defect of some sort in the manufacturing process?

 

[spkrdctr]

If it has the hum without the input signal connected it is broken. It could be many things. A good technician should be able to fix it fairly easily. If you want to mess with it, that is fine too. It all depends on how much you are willing to tinker with it. A real repair would just be a couple of days or so. Let us know what you do and what fixes it. I'm interested!

 

[khenegar1]

email martin logan service and explain ur problem ur having with the grotto they might have a easy fix for u. i emailed them recently with a question about my summits and they responded with an answer the next day.