Tube Amp, Preamp upgrades -- what did you do that improved your units?

@axo0oxa Thanks for your caution. It creates some indeterminacy to do multiple caps at once, but if it works, it works big. That's a gamble, and if there weren't other quicksilver owners testifying to the benefits, it would be perhaps too much. But there are and so it's not. I'll let folks know. My mind is made up. 

Good for you!  Only personal experience will allow you to determine whether benefit worth the cost. I expect you'll find the benefit well worth the cost using any of the top flight caps. And aren't all moves in audio taking a chance, purchasing new equipment is as much, perhaps a greater risk. Too many allow fear of failure to interfere with progress.

No on upgrading transformers. They are good, high in quality and function.  

Good to know. Thanks. @decooney 

@hilde45 Did you ever complete your QS cap upgrades? Reading this thread its not clear which QS model you are working with. If you have a newer QS item I do believe the capacitors if white in color are already Film and Foils if you replace these with any kind or metalized polypropylene cap you're most likely doing a down grade. In almost all cases a film and foil cap will be sonicly superior to a MP regardless. Mike at QS now has available on the QS website Film & Foil capacitors to replace common QS sizes .27uf, 2.0uf, and .056uf I believe. If yours are yellow in color or not identical to the new QS caps you should consider the QS labled film and foils. Im currently updated an older QS full function preamp that seems to be using older QS Metalized Polypropylene caps. I will be using the newer white film and foils from QS. You can view my progress on lowpower audio on youtube.

@hi2alex2 Yes, all upgrades are completed. Amp and preamp sound improved to my ears.