BIG fan of Nelson here, starting with DIY B1 buffer, as great as people have written about above. Had F4, aleph 30 and now F7, best of the bunch for me so far (xa25 is on my wish list for the future). Had many other amps too but his class A designs combine all the best qualities for an incredibly satisfying listening experience. He is so generous with his time and advice, answering emails and writing on forums, great sense of humor in his writing too (wish I understood it all!) and that never ending curiosity driving him to the next innovation - wonder what the sit-3 will be like.
