Vibration control. Tube equipment. What's the best way to do it ?

+1 Springs. I was spiked now I'm bouncy. So much better. 

I use any number of solutions depending on voicing I'm looking for. Mostly I use diy sandboxes made from Baltic Birch plywood, various sized up to 20" height for mass loading of my direct drive turntable, various top plates including various depth aluminum plates with vibration sinks attached via structural glue, wood top plates made from Maple or Baltic Birch. and then a variety of footers including soft/sorbothane type materials, ceramic and stainless steel ball bearings, the Nobsound, Stillpoints, finally I diy custom stands from which I hang equipment via high test fish line. All this sits on a 2" thick fireplace hearth made from concrete on suspended floor supported with jack stands.

sns, what is the difference between Maple and Baltic Birch ? Different sound signature ? I've never used anything but Maple.

I would put a set of Nordost SortKones under the amp. You could borrow from a dealer if you have a relationship, or buy some used and resell if you aren't happy with the result

I am a believer in draining away resonances from the components- and any component, not just tube amps, speakers included, as opposed to attempting to "absorb" it, or convert the resonances into heat. This is the approach Live Vibe takes.

The way to do this properly is to remove the wood, and have the component rest on the cones, which contact the floor. The wood is preventing your cones from doing their job, which is to drain the resonances from the component. The cones effectiveness would improve if you added their coupling discs, but it would improve even more if you had one of their platforms, which come with the cones and coupling discs.

Proof is in the pudding, I have them and they work. I can’t say if they are better than the vibration converted into heat approaches, as I haven’t compared them to HRS, Artensania, or Symposium, but they absolutely clean up the sound, improve clarity and reduce smearing much better than my old Solid Tech reference rack did, which uses the spring isolation method.

As with anything you have to listen and see if you like the improvements. It is possible one’s music is too lean, too clean, and they already have too much separation between instruments, and they may prefer more smearing and muddier bass in their music- it's possible.