Feedback through turntable


My system consists of a McIntosh C2300 preamp, MC452 amp, MCD500 SACD player, VPI Aries 3D with Ortofon Cadenza MC cartridge, Manley ChinookSE phono stage, PS Audio P5, Sonus faber Cremona Auditor M speakers and REL B1 Sub bass system.  My issue is with turntable use only; SACD has no issues.  On my pre when volume is +55 (peak at 45watts) I start to get feedback through the turntable - a sort of low freq sound, back off volume and it goes away.  My Auditor M speaker is about 3 ft away and in front of turntable.  I do have a rumble filter (KAB) installed between preamp and phonostage to help with sub woofer pumping.  Due to room layout I cannot rearrange the setup/move turntable.  My turntable is on a 2.5" block of wood and that sits on 4 isolation blocks via spiked feet.  Any thoughts how I can eliminate this problem?  Harry Weisfeld with VPI states he has 4 15" woofers (JBL Everest) near his Prime Signature setup with no issues at all.  Why am I having this problem and how can I eliminate it?  Thank you in advance for all feedback.
miner42
My main listening room is on the second floor, carpeted on a suspended subfloor

Is the 1st floor,  the main house floor also suspended ?  Do both floors use horizontal wood beams? 
miner42,

Did you ever try ct0517's dance tip? If you are embarrassed to dance, follow his directions without the dance. If you're getting the low frequency noise this way, something in your tt isolation chain is not set-up right or is not able to isolate effectively for your particular situation.

What type of audio console are you using?
If you haven't already watched the Townshend Audio YouTube video showing how a speaker on a concrete floor reacts to vibrations, you should. (bdp24 has talked about this in other threads).

Then think about if a speaker on a concrete floor has this much vulnerability to vibrations, surely your tt on a second story will be magnified multiple times over.

Food for thought.
I have been to older audio friends homes where their children have left. (yeah right - will believe it when it happens to me) ......anyway.

So the couple, find themselves with an empty bedroom/s upstairs; Usually (She) doesn’t want the stereo on the main floor. So usually (He) is forced to use one of the bedrooms upstairs. All wood suspended floors have the capability to produce what I call the 6 O’Clock train effect as bass and volume increases. And the higher you go 1-2-3 suspended floors, the worse the effect can get.

All it takes is one of the full range speakers and or sub to be placed above one of the same horizontal beams, as the one the turntable stand sits on. They become joined at the hip - so to speak. As the volume increases, its like that 6 O clock train going by. A suspended floor is never an ideal spot for a resolving turntable. If the problem is bad enough and keeping you from enjoying your system at those levels that get the .....endorphins flowing..... then...

locate the nearest main side wall that supports the house. Not that flimsy wood studded wall between rooms. Attach a shelf/ves to one of the main support walls. Another option - a little more extreme.... is to hang the shelf from the ceiling. 8^0

**************

then there is the other fellow, same suspended floors, that puts all the gear in one room except the speakers. The speakers go in the room next door.
But guess what - they are still sharing the same horizontal wood beam - so - still joined at the hip ...... guess what happens....

thats right ..choooo. choooo !! some Sat morning funny
ct0517,

I think we are on the same page. This has been my personal experience.

I hope we hear from the OP? It is now up to him.

Happy listening.