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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
totem395
390 posts
 
Having feed back issues and running the table with a cover is 
never a step in the right direction. I can't believe I needed to 
say that.

Step back and look at where the problem begins the acoustic 
characteristics of your room and what you are adding to it.

Start with implementing room treatments rather than
applying this or that band-aid. The gains will far outweigh
other options. 







 




 


lewm
12,590 posts
 
Totem, You wrote, "Start with implementing room treatments rather than
applying this or that band-aid."  Isn't there an internal contradiction in that sentence?  Some would classify room treatments as a bandaid. Not that there's anything wrong with that.  The simplest first steps would be to make small changes in the positions of the speakers or the turntable, respectively, and determine what that does.  Such experiments cost nothing.  The OP has such plans afoot, I should hope.
rotarius
431 posts
 
Some strange replies posted here.  There is no harm in using a cover during play to see what the results will be, so why not experiment?  As for standing waves, resonance etc., it is all very dependent on that particular system of components and materials, impossible to predict by anyone and I am sure most people giving advice here have never used a vibration analyzer, they just go by their perception.  Try everything you can, experiment away:) 
stringreen's avatar
stringreen
6,388 posts
 
Get in touch with Edensound Audio and try out their BearPaws....large brass cones.  I have a Superscoutmaster with a 3D arm and these made a HUGE difference...no down side.....the sound is better by far, and I can do back flips, and never get feedback from the turntable. 
slaw's avatar
slaw
20,526 posts
 
I use machina dynamica super stiff springs between my tt platform and my wall mount. This is an inexpensive option that works very well.
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