Isolation feet/cones for PS Audio NuWave DSD DAC

@agriculturist to get this to work you need to know how the weight is distributed in your amp. Given the heavy transformers at the back of your amp this is where most of the weight is. In this case you need to place two cones under the rear, and one centered under the front.

The method to do this (which is tried and tested on my 90lb+ VTLs) is as follows -- and which always gives you a stable load to work with (except in step 3)

1. Lift the back left and maneuver a cone into place -- avoid screws or other obstructions, it may help if you have already removed the amps existing feet if these are bulky and get in the way
   
2. Lift the back right and slide in the second cone
3. And now the trickier part as you will be bearing most of the weight, lift the front (hand just to one side of the center line) and insert the third
4. Finally adjust the exact positioning of each cone to fine tune the sound, it may make a big difference

I can do this easily in my amps even with limited access so I think you should have no problem especially as from pictures the weight distribution on your amps is symmetrical left to right. The one tricky thing with your amps is that they are deep so reaching to the back is a pain, not sure if you have side access

To ease things you may want to use some dimpled coasters under the spikes, this makes them easier to slide -- this will also change the sound, maybe better, maybe worse. Personally I use Marigo custom slab coasters under my Marigo Mystery Feet, gives most of the benefits of a full Marigo shelf without the expense

@agriculturist the adhesive is a huge no-no. You want to avoid anything that will introduce another interface between your footer and the amp. Some sort of squishy gluey stuff will just reduce the effectiveness of the coupling amp to footer. Many manufacturers make add on footers with threads that you can swap for the OEM feet but I don't think this is necessary. If you follow the setup method I recommended and/or use some shim blocks as @lak suggested you should be fine. I actually went so far as to buy some low jacks to assist when I needed to swap the feet under my amps stand while leaving the amps in situ -- something like this may make your job easier (although they have a minimum height of 4.75" which is still pretty high)
https://www.strombergcarlson.com/rv-steps-step-accessories/stabil-step-jacks/stabil-step-jack-model-jss-4/