My PX4 valve amp has always been a problem. It was great in many ways but when i swapped to the other 250 globe amp it showed these problems, one was a lack of liquidity. My main 250 amp has 1930-40s Freed oil filled chokes, critical for its brilliant liquid sound. PX4 does not, and it shows. So how do I give that amp what it demands. Them I spied the answer, Audionote 0.22 paper in oil filled capacitors. Out came the Duelund 0.47. Am I crazy you ask, Removed the choke input setup and the extra caps, (less is more) now in one fowl swoop, it is brilliant, liquid, so liquid you can cut it with a knife, big soundstage, dynamic, grainless, This amp just needed this cap, the synergy is amazing. Before you rush to buy Audionote oil caps these are not the new Audionotes oil caps, the ones I am using are 5-10 years old, paper in oil. The new Audionote Mylar oil capacitors look the same and may measure better, but sound ordinary.