I bought a Sonic Impact amp and listened to it for some time. It does a strange thing in that it compresses the signal at anything over a whisper and sounds very strained and tone-shifts at any thing around conversational volume. At first it sounded like a panacea for expensive equipment but over time it has not held up. I used it with very efficient speakers and some not so efficient. The small monitors I have are rated 94 db so I don't think the problem lies in a mis-match. Unfortuneately it seems there are no free lunches in audio. The Gainclone is a much better sounding amp but after the full treatment it too becomes a little pricey. I'm since returned to tubes and looks like that is still the way to go. Too bad tubes are all getting so expensive.