How to isolate turntable from footstep shake or vibration

I questioned the need for a SRA platform on my preamp and was assured by several that it was absolutely necessary. And when I asked if I also needed Stillpoints, I was definitively told that using them also would defeat the function of the platform. That it was designed for the stock rubber feet.
SRA has a military division which makes, among other things, vibration treatment for nuclear submarines. Thus, the Ohio and Virginia Class names for their platforms.
And about my preamp, if an electron microscope uses a vibration devise, why not a preamp?

Slab of PU foam or SorboThane between a cookie flagstones or marble pastry slabs 

Couple^^^

Mijostyn, if everything boiled down to your personal experience, the world would be a simpler place to live, for sure. Tubes ARE microphonic, regardless of my or Ralph’s opinion. FYI, you may pay extra for quiet tubes from certain vendors, but what you’re paying for is lower than average levels of electronic noise, a good idea in a phono stage, but that spec says nothing about microphonics of that particular sample, which is a separate issue not usually measured by vendors, because microphonics will vary from one installation to another, even from one tube socket to another. 9-pin miniature triodes like your 6922s have a lesser tendency to be noticeably microphonic, compared to, say, octal base triodes like 6SN7 or 6SL7, so you’ve lucked out with your unit. But know that tubes can also become more microphonic as they age. Also, since the 6922 has modest gain factor, I am guessing your phono is a hybrid design, using transistors in combination with the 6922. This is another reason you might feel immune to the problem.

If the military can make electronics that are immune to vibration so can the high end audio industry.

Yup! One of the ways the military does it is vibration mitigation solutions- for example EAR makes a bituminous based extensional damping compound that gets used in submarines. When tubes were involved they used isomeric mountings on the tubes sockets to limit vibration transmission to the tubes themselves.


BTW 6922s tend to be more microphonic than the 12Axx family of tubes since they were intended for instrumentation rather than audio. That you have a set that is so low in microphonics that you can't hear it when tapping on them is really unusual- so much that its in the realm of outright miracle.