Audio Research Reference 3 Bypass Caps Question


Hi,

I have a 2007 model that does not have the silver caps with yellow ends as depicted in the photo of the back of a Ref 3.  Are these the bypass caps added just after the introduction of the model?  I am curious because when I read the description of the location of the caps, at least one person says they are on the other side of the board from the big red tubes with goldish bands.  Those I do have!  So if those are the bypass caps, what are the ones mentioned first that I am missing.  Thanks for any info.  

Please see photo from back of Ref 3 for reference.  
https://www.arcdb.ws/model/REF3  
hhawk
Thank you!  I really appreciate the info and feel better about my not having an updated model.  Since it had been working fine for 13 years I had been wondering if it would be worth having it updated. 
BTW Audio Research told me they no longer offer this mod so I would have had to find someone else to do it anyway.  
It appears that you are correct, but IMO/IME bypassing coupling caps isn't a good idea. Different caps have different extended series resistance, they have different dielectric constants (even if made from the same material) and as a result the signal gets smeared if the bypass is present. Part of this is that the coupling cap at the output is directly involved with the output impedance of the preamp (being a series impedance with it). IOW when it comes to coupling caps, you give it your best shot with the best cap you can come up with. It won't be perfect (nothing ever is); if you want to move away even further from perfect. then go ahead and use the bypass.

Bottom line- I bet it sounds better on a good system without the bypasses.
I couldn't get the photo to show.  The silver caps with yellow ends are on the same board and side as the 4 tubes but on the opposite end of the 4 tubes.  These are the ones I am missing.