The owner of the company is on here occasionally, he should be the one to explain why he sells kits and not finished products. There are plenty of companies who sell finished OTL's but DIY kits allow the customer to save manufacturing costs and adapt the amp to their liking. Open up a prebuilt amp and start playing with it and you just voided the warranty. Want plug and play? Buy a Crack amp someone built. They are also a good way to learn soldering techniques and component recognition. There are plenty of things that make the Crack amp enjoyable, you have so much versatility in shaping the sound to match your tastes. It is not too hard to match headphones to the amp since you are starting out with high impedance headphones only. Try to think of another amp where folks try so many different sets of capacitors, tubes, control pots, and chokes to shape the sound. The fact that you build it lends itself to your going back inside and understanding later changes you might make. I own a Valhalla 2 and I can swap tubes, that is about it. DIY amps are more geared to those who like to tinker with them, if that is not for you, so be it.