Sound Technology 1000A units are going for more than I want to spend and I don't see any docs at all available for the Goldstar SG-4015S units on eBay. The Sencore SG-165 doesn't seem to come up often, and performance is a bit dated. I'm thinking of building something to simply drive my HP RF gen. Does anybody have an opinion on the Pira board? I want something that I can easily build, repair and maintain. Or, does anybody know anything about the Goldstar units?