Preamp Output Capacitor: Mundorf Supreme vs. Supreme Silver Oil


Anyone compared the bass response of these two caps?  I bought the Supremes for trial purposes and really loved what they did to my system's imaging (front to back layering) and immediately bought the Silver Gold Oil Supremes.  Unfortunately while they were smoother, more beautiful, and even better at imaging, they had no bass (actually, they lost bass as they broke in).  Anyone know how the Silver Oil's fit into the line?  

I'm using them in a Don Sach's DS2 Preamp ( https://systems.audiogon.com/systems/7983).  

Thanks.
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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.