Preamp Output Capacitor: Mundorf Supreme vs. Supreme Silver Oil

If I am going to be in a minority, I don’t mind having Ralph from Atmasphere in my corner.  Over the years I have noticed that Ralph’s observations often agree with my own.  
That said, I am not sure I agree with Ralph’s implication that problems with bypass caps are more of a problem on highly resolving systems.  As I said in my post on the previous page, I have experimented with bypass caps for 40 years and my gear from way back then would not be considered highly resolving by today’s standards, yet the sonic problems with bypass caps were evident in all of my systems.

I think the different reactions to bypass caps are more related to different listening priorities.  To my ears the positive things that bypass caps can sometimes add can be described as “Hifi spectacular” artifacts—-bigger soundstage, more specific imaging and seemingly more inner detail.  Certainly I am not opposed to hearing more detail, but for me the “improvements” caused by bypass caps are artificial.  They come at the expense of a skewed tonal balance where the HFs are emphasized and have an artificial sheen or glaze, and the upper bass/lower midrange becomes lean and lacking in natural warmth.  The degree of skewed balance changes with different caps but the direction is always the same.  
In addition bypass caps make the sound less coherent: music sounds like it’s coming from a 3-way speaker rather than a single driver.
Furthermore, with a truly high resolving system I find I hear just as much inner detail without bypass caps.  The detail is just less hyped.

Some people hear and like the “Hifi spectacular” sound and perhaps don’t notice or aren’t bothered by the negatives.  Other people find the more spectacular sound artificial and find these qualities make the music less natural.  
At the end of the day, if you like the sound with bypass caps then go for it.  But you really should try removing the bypass caps at some point after they are fully broken in and you are fully used to the sound.  You might just find you actually prefer the sound without the bypass caps.

And that's why it's a personal preference, in my system bypasses made my system sound more real, not less. It has nothing to do with fake hyped detail. 

I tried the Duelund .01uF tinned copper cast bypass caps in three positions and came to different conclusions each time. 

I liked them on the .47uF interstage coupling caps of my Coincident Frankenstein 300b monos.  Thought the sound got more real and natural with them in the chain.  Couldn't hear them at all over the 1uF Miflex output capacitor on my Don Sach's 6SN7 preamp.  And heard the smearing effect when I put them on the 4.7uF cap (Clarity at the time) used as a high pass on my Coincident PRE's tweeter.  

I forgot to add that IMO part of the issue with bypass caps has to do with the size of the coupling cap you are bypassing. Generally speaking I've not liked what larger coupling caps do as they impose more coloration. But in some cases they have to be used- such as at the output of many tube preamps and also driving output tubes in a power amp. For this reason I've avoided coupling caps in these specific areas (instead I employ direct-coupling) as this allows me to use much smaller values overall. I can easily see resorting to bypass caps in the case of larger caps- 1uf and above in particular.

Exactly Ralph, my Amps use four 2.2 value caps per monoblock, one for each tube. When running just a single large cap the sound is definitely shelved off in the highs, scymbals sound rounded off for an example. Adding .22 value caps opens the amps up, while still sounding very clear and clean, it just adds some sparkle up top making the system sound less dark.