To follow up on what Lynn just posted. I spent my time rebuilding vintage tube gear with modern parts, then I decided to make my own and always tried to make it reasonably affordable and be better than the vintage gear. The Raven and Blackbirds are a departure. What is possible if you remove the cost constraint, and instead build gear that will sound the best without regard to parts costs? The Raven and Blackbirds are built with the best parts for sonics so they are expensive. They are not built in insanely expensive cases, nor do they have a dealer network to add to costs, so they are not stratospherically expensive. They are built with very nice panels and in solid cherry or other solid wooden cases. They are expensive to build, and I understand that prices them out of many people's budget. So something like the Bottlehead kit mentioned above is very cost effective, and I have no doubt it sounds wonderful. My previous preamp and amps were very good to my ear and were cost effective. But they do not occupy the same sonic universe as the Raven and Blackbirds. Nor should they. The parts cost for the Raven and Blackbirds exceed the sale price of the other gear.
Obviously, the lower cost gear sounds very good and will provide the foundation for a very pleasing stereo system. Diminishing returns is always at play. But it is fun to make the best sounding gear you can, and then worry about the price.....