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
geoffkait,

I understand where you're coming from. I know that lead can deaden the sound if not used thoughtfully. I should have then said, the shelf that supports the component I need the additional weight in my system to get the proper loading, I use a BDR shelf that doesn't react to the addition of lead like other materials. I have several weights of brass with points that work well in other areas.

My main point was, for a tt, where level is critical, I find in my system, I like to have a support structure that has a built in leveling adjustment. I find if one has a tt with adjustable feet, it's best with them screwed all the way in and do the leveling elsewhere. In some cases where finances are a major factor, this may be a way to go at some later point. Another positive is that you can then play with better (feet options) on your tt that will better address the sound quality while still using the springs under a tt's DIY shelf.

Having said that, the addition of marble shelves or any other shelves, while adjusting for load, will not help with the leveling. The bags of lead shot or brass feet strategically placed is an option that can kill two birds with one stone, so to speak.

The important thing is to get started and all of the many options available to you will be a good upgrade in the future.


Springs are self leveling. Absolute level is obtained by slightly moving one or more spring using thumb and forefinger. Obviously the load should be distributed uniformly when level is an issue. Tip: for CD players absolute level of the spinning disc is usually not the same as the level of the top of the chassis.

Addendum: I actually like brass just slightly more than I like lead, which I loathe. They both seem like such a good idea, too. Glad to hear you're are able to live with them. 😃
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.
(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
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