This is work in progress, but I thought I share it;
I made body for Blue Jinn's exellent royer pcb some time ago,
Aluminium tube , mesh was glued with epoxy and long pcb stands connecting top and bottom plates.
Röde capsule&holder.
I didnt like the thin aluminium and since I happend to have some REALLY sturdy 5mm thick steel tube,
I thought I'd try how it would dampen the body..and it did.
original body was painted and this tube was glued (with eleastic)glue on top of that.
I'm still working on getting the mic's background noise as low as possible;
I place the mic in a "quiet" place and crank gain on preamp to full..
first modifying groundings on mic on psu got noise down about 10dB.
then ripping my psu back to basic and slowly adding capacitance and coils got me few dB'slower.
attached current version of psu.
all this filtering on HV compared to basic royer voltage tripler psu dropped noise only 1-2dB,
while on the heater side difference was more drastic.
Finished PSU.
with previous build I didnt notice any noise with same kind of psu,
but maybe I was just too paranoid with this build;
Funny that that first I had grounding issues->psu didnt make much difference.
once that was fixed I noticed the mic grille mesh was too open and it was picking rfi/emi.
after all that was fixed I noticed small improvement in noise with choke added in heater supply
and thats what I ended up with.