1. Buy three brass speaker spikes and some epoxy (I did say almost free).
2. Glue the spikes to the bottom of your amp.
3. Sit back and enjoy deeper more articulate bass, better detailed mids, smoother highs, and a larger soundstage.
4. (Optional) Kick yourself in the ass for spending hundreds on cryo-snake-oil cables in a vain attempt to achieve the same thing.
I suggest a heavier spike with a flattened point for use on tables. Always use brass. It's a tiny thing, but it sounds better in my experience than steel or wood and definitely better than aluminum. I use these: http://meniscusaudio.com/extra-points-p-208.html
Your epoxy should be something that dries hard and dense... Nothing rubbery. The point is to achieve a solid connection between spike and amp. I use SureHold Super Glue, because it forms a hard, strong bond but can be knocked loose and sanded off if needed. For a completely permanent bond I suggest J-B Weld Kwik-Weld.
The benefits of three points of contact versus four is that unless a surface is perfectly flat (and I mean perfectly, as in laboratory-level) there will be minute movement. One point will always not be in perfect contact. Three points of contact will be perfectly solid even on rough and distressed wood surfaces. Solid contact equals less vibration. Less vibration equals noticeably better sound.
While there are different schools of thought on this, I like two spikes up front (roughly where the stock feet would be) and one spike centered in the rear of the amp. My reasoning is that I am fiddling with the front of the amp (plugging/unplugging headphones, volume, etc) more often than I am with the rear, so I like it to be stable in the front.
Edited by Earbones - 4/26/14 at 4:48pm