I also use an Argosy. I don't have a thump on CW, but it does thump on AGC action, actually it pops. So when using headphones its amplified a lot. Argosy's receiver is very good. It's a quiet analog receiver that does not have all the phase noise of the newer ditital ones of today. I like the quiet noise floor. It's my favorite CW rig. 73, Don, NN8B