I also recommend Kevin Deal of Upscale Audio. I bought 2 NOS Telefunken E88CC/6922's.
Here is my excerpt from: The ups and downs of tube vs. SS...
'Also while researching phono preamplifiers I found out about 'tube rolling'. However I thought that tube rolling is a expensive proposition even though the tubes you roll maybe not that expensive, after rolling 5 to 6 or 7 pairs of tubes, the money spent would add up pretty quickly.
So I decide to go for the gusto and buy up. I bought a pair of NOS 6DJ8/ECC88 Telefunken West Germany with diamond mark matched pair for $195 plus Tektronix 576 curve tracer matching for $20, shipping $10 and $4 for insurance for a total of $229 from Brent Jessee Recording and Supply, Inc. Keep in mind it is very important that you buy vacuum tubes from reputable dealers. That being said Brent Jessee Recording and Supply, Inc. has a 30 day return policy with a 20% restocking fee. After less than 30 days I decide to return them.
After seeing Kevin Deal's of Upscale Audio NOS Telefunken E88CC/6922 youtube video I bought a Platinum Grade, Cryoed, matched pair of NOS Telefunken E88CC/6922's for $454. For a total of $853 I bought a Parks Audio Budgie Tube Phono preamplifier and pair of NOS Telefunken E88CC/6922's vacuum tubes with the transparency, depth, wide soundstage, and dynamic range as described above with an added 3 Dimensional sound quality I had never heard before. '