1212m is a good computer source, clean sounds.
HP-200se comes with the best EH tubes(gold plate pins).
Maybe try the tube rolling after 400~500 hours burn-in, then you will heard the really sound of this HP-200se.
Telefunken are good choice, but they are not a cheap one.
Replace table I've found:
12AX7-> ECC83 7025 ECC803S CV4004 M8137 E83CC CV492 5751
12AU7-> ECC82 E82CC 5814 ECC802S 5963 CV491 CV4003 6189
Hope these infos can help you.
BTW, HP-200SE is nice sounds with nice looking. Will post some reviews about your HP-200SE?
Happy with tube rolling!!!
Put the Little Dot with my Wadia last night, it really bring me some wonderful sound.
There was totally different sound with a cd walkman, ya! this is very fantasy.
I like the Little Dot, but PPX3 is still my best headamp.