Preamp Output Capacitor: Mundorf Supreme vs. Supreme Silver Oil

t_ramey, thanks. I’m also looking at 2.2uF values for my preamp and I now see the prices are on par for 630 volts rated model when buying a pair and ODAM pair is cheaper for the ones rated at 400 volts.

@kalali The Audyn True Copper Max are excellent caps. I recommend that you install the ODAM in a different component that can benefit from high quality caps. I bet that the True Copper and ODAM will provide excellent synergy. I use copper foil and ODAM caps in my system with great results. 

Thanks for the input. One quick and hopefully non controversial question: do any of these capacitors need to be installed in a specific direction even though they are not marked for direction? I have seen some tube amplifier building/repair instructional videos where the designer/builder uses a special device to measure a certain parameter to determine the “correct“ direction for installing the capacitor, e.g., foil side towards the tube socket, etc., or something like that if I remember correctly. He claimed it makes difference. Just wondering.

Yes. I need to understand circuits better to give the technical reason why, but in my pre the outer foil points "upstream" (away from the outputs). The mundorfs are supposedly non-directional, but I’ve seen a video where people hook it to to an oscilloscope and show that it passes more noise in a particular orientation.

Here’s a decent discussion on the topic: https://el34world.com/Forum/index.php?topic=11427.0

Thanks for the link. I found the video where i saw the capacitor polarity topic discussed.

https://www.youtube.com/watch?v=BnR_DLd1PDI&feature=youtu.be

P.S. Sorry if a bit off topic but might be of interest.