A month ago I found 4 tubes 6n1p in my stuff, so I decided to use them. But what's the best thing you can use 4 russian tubes - of course, a headphone amp. And I do need one now since I am listening to music on headphones almost 5-6 hours per day.
I found a pretty good schematic for 6n1p headphone amp here (http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=bender_prj.htm) by Bruce Bender.
I ordered all parts that I was missing and here are they.