Silverears

Hello, I have recently purchased a pair of Stax omega 2 headphones and would like to build myself a KGSSHV amplifier. Could you please advise me how I could obtain the appropriate circuit boards. I'd also like some advice over the on-board or off-board model for someone who is capable but not an expert ? Fortunately my father is a retired electronics engineer and will assist in the construction and power-up. Kind regards