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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
cleeds
2,065 posts
 
perazzi28
Some woofer pumping will be present as a good preamp will have frequency response near DC.
This is mistaken. If the cartridge is properly matched to the arm, and if the rest of the phone system is properly set up, there should be no woofer pumping at all. Absolutely none. 
slaw's avatar
slaw
5,785 posts
 
@bdp24, @toddverrone,

FIM made a ball n" cup device as well that was priced lower than the Symposium jr. Maybe still in production???

I almost offered one of my Symposium jr. sets up for sale, thought about it and decided to keep.

They were offered w/ two levels of ball bearings, one of harder strength. (Tungsten)??

I took it one level further and acquired ceramic balls. My project at this time was my VPI HW-19 mk IV that i"d taken way out of stock.

The ceramic ball bearings were a step up in this particular setting, adding major transparency... the highly resonant plinth/base of the VPI was HARD to overcome!


slaw's avatar
slaw
5,785 posts
 
You both may find this of interest..

I've fabricated a 3" maple platform that I've recessed 3 Symposium jr. (cups) into (flush) w/ the top of the platform.....on the bottom, I've a 1'8" recess for my Super Stiff Springs.

An effective,versatile platform that can be used in various applications.

I'm currently using it in my similarly modded rack that my amp/conditioner rests on.
slaw's avatar
slaw
5,785 posts
 
1'8" = meant to write 1/8".
slaw's avatar
slaw
5,785 posts
 
@bdp24,

This may be an optimum platform to try your future plan?

I can provide some pics if you want?

Happy listening
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