Annoying bass rumble/feedback problem..

[Mark1975]

Ok I have a problem that I hope somebody could help me with. It's not a new issue as I've searched for and found countless similar queries, however being the novice that I am, I don't know where to start when it comes to solving it. I have a soundlab G056C turntable, which is running on a Sony STR-DB930 receiver and two B&W DM110 speakers. I'm sure that this is a far from ideal setup, however it was all I could practically afford.

The problem I have is a really loud bass rumble/feedback issue when I turn the volume up past a quarter of the way. I tried investigating this today and noticed that when I lower the turntable lid, it reduces slightly, but is still a problem. I also noticed loud crackle and feedback when I tried fiddling with the RCA leads, which also caused the speaker cones to flutter like crazy.
The turntable and amp are placed next to each other on a purpose built cabinet, whilst the speakers are placed on two wall mounted shelves. One of the shelves is approximately 800mm above the table/amp cabinet, whilst the other is on the other side of the room. I thought that the problem could be that the table and amp were too close together, but the problem was still apparent with the turntable on the floor. Interestingly however, I found that when I physically lift the turntable off the cabinet and hold it, the rumblestops?!
I've read about turntables needing to be grounded but whilst my amp has a grounding post, the turntable doesn't. Am I right in thinking that as this particular turntable has a built inpreamp, it doesn't need to be grounded to the amp?
Sorry about the long windedness of this post but it is really bugging me, I just want to be able to hear my music loud every once in while!Im not looking for audiophile quality, just a half decentsound at a higher volume occasionally.The quality is fine at normal volume.
Any advice on how to combat this will be gratefully received!!

 

[MajorFubar]

If it only happens when it's loud are you sure you're not getting feedback from the speakers, ie being picked up by the cartridge? The crackles you're getting because of poor connections at the RCA socket/plug are possibly a separate issue. Easy to find out, try it with headphones.

 

[Mark1975]

Hmm yeah could be.I didn't think that this would be the cause, what with the speaker being on seperate wall mounted shelf.However, the DM110's are big speakers so it is likely that the one above the amp could be causing feedback.I'll try and move it after work tonight and let you know how it goes.The thing is though, I'm limited as to where I can place it in the room...plus as it's an old house,there is only one plug socket in here!

 

[hybridauth_Facebook_100004211376004]

If your b&w's are on a wall mounted shelf,then I'm assuming that they are practically against the wall,this is definitely a recipe for boomy bass given the size of these units.try repositioning them in the short term away from the wall and compare,you may find a lot of that rumbling bass has disappeared.

 

[stevebrock]

The low frequencies from your speakers are being picked up by your cartridge, I had the same problem when I had my hi fi rack in an alcove when i moved housed - I was wondering for days WTF as I had it in an alcove in the old house - but all rooms are different.

My Gyrodec is as far away as possible - not ideal - but what room is when you have other considerations ie family