What is the most important cable?

I was told the source. But I would think the speaker my resonong is that everything runs throught the speaker all your sources. From what I read keeping the cable all the same brand doesn't matter because each cable handles a specific need but I would keep the tupes the same. For example audioquest doesn't play nice with Kimber since audioquest is a solid core and kimber is not.

Me I use all the same. Or trying to.

Amp for power would be the most important especally tubes this is because the amps sraw the most power and amplify the most noise.