Preamp Output Capacitor: Mundorf Supreme vs. Supreme Silver Oil

Ralph is far smarter than me and I would never argue with him 🙂.

A quality, educational discussion... Thanks. 

Audio research uses bypass caps and their products sound amazing. It must come down to personal preference. 

With my Rogue audio m180 darks they are traditional push pull transformer based tube  amps. I have tried both options, with and without bypasses. The coupling caps in my amps are 2.2 value and sound more open with greater extension and air with .22 value bypass caps added to the circuit. Without them it is more midrange oreintated and darker sounding. The treble stills sound clear and clean with good recordings, on my Revel 228 be speakers on the Chet baker "Chet" reissue you can clearly hear front  to back separation and his lips pressing against his horn without smearing, you can literally hear the brass instrument. Very clean and high resolution.  

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.