IERC Tube shields?

If these are the old tube shields for military gear, I tried them on my preamp and phono stage last year. The ones I tried were very firm fitting, and had to be pressed on the (6922) tube with some force, compared to tube sox.

On my equipment the sound was somewhat compressed and over damped sounding compared to no dampers at all. Could be that because I was happy with the excellent NOS tubes in the circuit, there was not place to go but down with the test.

I might add that other brands of tube dampers have been removed from my system as well. I once believed in them and have now come full circle, finding that select tubes with no dampers at all is the best way to go.

i have used them in the past in a tube phono stage and found they helped in some way and hurt in others. Less body more focused. I have several of them laying around, let me know if you would like to try them, I can send you some.

I have used tube coolers, not tube shields, on 6DJ8's/6922's and 12AX7's. However, I found that rubber "O" rings purchased at a hardware store were cheaper and more effective in taming microphonics. I put three of different thicknesses on each tube. Space them out so one is at the top, one in the middle, and one at the bottom of the tube. They don't melt or weld to the tube, and they can be used again and again. The 6DJ8/6922 benefitted the most, tending more toward microphony than 12AX7's.

Thanks folks!!!