2. analog
  3. 128511-1637

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
bdp24's avatar
bdp24
9,514 posts
 
Sand is good for adding mass, in place of lead. Put it in little "snack" sized ziplock sandwich bags wherever needed. The only spring isolators I've found that offer height adjustment are the Townshend Audio Seismic Pods, but they ain't cheap, $150-$200 each I believe.
slaw's avatar
slaw
20,546 posts
 
(I use these types of things on the platform and not the component itself.)

bdp24, You're absolutely correct. Sand is very inexpensive as well!

Geoffkait, Thanks for allowing me to explain my process more than I initially did. I have a new DIY wall mount/equipment platform I'm completing in (my mind). I will be ordering more of your springs in order to make it a reality.

Happy listening
13blm's avatar
13blm
63 posts
 
Cones and blocks do nothing for isolation. I manufacture a heavy magnetic levitating damped footer that is often effective in your situation. I have a new less expensive version than the one on my website. 
Regards,
Bruce
Anvil Turntables

lewm
12,604 posts
 
We've heard from everyone but the OP.  Have you done any of the recommended experiments and what were the results?  Inquiring minds want to know. Thanks.
slaw's avatar
slaw
20,546 posts
 
lewm,

My thoughts exactly.

13blm,

Not to get into a debate, but I've heard the difference in my own system of various aftermarket cones, stillpoints etc... Saying they do nothing for isolation is just plain wrong in my experience. Maybe we could get into the symantics of isolation vs. effective ways of dealing with
vibrations/resonances but I won't do that. I just report on my experiences.

Good luck with your products!

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