vibrapods -- which component?

which component makes the most difference with vibrapods? I don't have a cd transport, but instead just apple tv feeding optically to Arcam Blackbox DAC, to Yamaha RX-A3000 as preamp, to Classe CAV75. which of those should I isolate for the greatest improvement? thanks.
Every item would benefit from isolation of vibration. I would start with the source equipment first then do the rest as you can afford it. Remember that the weight is very important as to how many pods you will need to use.
I tried them under a number of components, being careful to select those consistent with the weights of the equipment. Checked them a couple months later, to find the donut shaped cushions gone flat(rendering them useless). Wrote two(very civil) e-mails to the Vibrapod, "customer service" addy, asking if this was somehow normal, never to receive a reply.
I have them under my bookshelf speakers. Wonderful result. Allows most all the energy (and microdynamics) to enter the listening space. I found them much superior to blue tac, and the many other interfaces (coupling and decoupling) that I tried. I like decoupling myself.
I suspect the thing with the lowest level signal, I.e., preamp, would be the most sensitive to vibration.
I just bought a set of four Vibrapods for my VPI turntable and it seems to work great.