Ceramic insulator cone under phono stage shocker!

Except cones are not really inherently diode-like.  We only wish they were.  They can approximate the action of a diode, if very carefully placed on a resonant shelf, on areas that act like vibratory nodes.  Otherwise, energy can go both ways through a tiptoe cone. To maximize any diode-like function, you have to listen to confined areas on a shelf, best done using a stethoscope while tapping on the shelf; look for small areas that do not transmit the tapping noise as efficiently as do other areas.  There you can place a cone and hope for a diode-like effect.

What most of you are saying about orienting the cone tips so they point away from the source makes logical sense to drain the energy...but for whatever reason in my setup they sound better pointing up.  However my arrangement is a little different.  My turntable sits on a BDR The Source platform with BDR cones (pointing up) between my rack and The Source platform.  I have flipped them numerous times and it isn't even close - I lose much dynamic range with tips down on the rack under The Source platform - in fact it sounds downright "thin" as if all the musical goodness got drained away along with the "energy".  

@three_easy_payments,

To me your situation suggests that your (rack, I assume) isn’t effectively decoupled from the floor or surroundings.

@slaw

I’ve actually considered the exact same thing and I suspect you’re right. My rack sits quite close to one of the speakers and the cones are probably dissipating some energy transferred from the floor or even sound reflections from a nearby corner. I have a Symposium rack with spikes that sit on four Precision couplers (maybe I should be using dampening pads and not couplers?) and I use Gaia III feet under my speakers but together they may not be enough to keep the seismic out of the rack. Cones pointing up may be the perfect workaround for me as it would be very difficult moving the rack considerably farther from the speaker. I have a couple of GIK tri-traps on order, one of which will go in the corner 4-5 feet behind the rack - this may helps as well. I have a 24x48 absorber wall panel behind the rack but the corner is untreated.

Thanks for weighing in.

The precision couples are doing just as they are suppose to....coupling your rack to the floor...not decoupling thereby exacerbating the issue, IMO.