He wrote "...Ei 6dj8". Ei is the abbreviation that a European company named something like Electrical Industries uses. They're available all over, are quite inexpensive, and certainly are among the best-value NP tubes around. Here's one source http://store.tubedepot.com/ei-6dj8eg.html among many. I've happy with my results with Ei 12AX7s, 12AU7s, and Tube Depot.
On your original question, here's an informed opinion about capacitors--
http://www.altavistaaudio.com/caps.html
.
On your original question, here's an informed opinion about capacitors--
http://www.altavistaaudio.com/caps.html
.