Forgive me for waxing nostalgic but I ran a pair of Quicksilver Monos for many years (damn, I can't remember what preamps I coupled the Quickies with). At the time I lived less than five miles from Mike Sander's house, so it was no problem getting silver-quick replacements for those soulful if highly neurotic 8417 output tubes. Don't look at them funny! At any rate, I eventually lost my patience with the ever-increasing cost of buying matched 8417s and bought a Primaluna Prologue One integrated. Been happily out of the amp trade-up game ever since.