Would this work for two conductor power cable?

I know the benefits of a three conductor grounded power cable but IF I use a two-conductor to replace the stock cable on my tube amp would the following be a good alternative?

First, I've read that a shielded cable is not necessary for analog equipment (such as my tube amp). I don't know why, or even if this is a correct statement.

If it is true, then I wondered if good quality loudspeaker cable - in an appropriate gauge - would be suitable as a DIY power cable?