Cryo tubes for Herron phono Preamp

For new tubes I have a very picky golden-eared friend that highly recommends Electro Harmonix 12AX7 Premium matched. I have been tracking down vintage 5751's for a bit of rolling in my pre. To each his own. (TEHO ?) :-) Enjoy!

Some work well others don't.Its a crap shoot... The mentioned Sovteks are a warm tube already and I would think the cryo treatment would make them even more so overly sweet. I have 3 versions of The Sovteks lp,lps, WXT and I actually think the Early 12ax7wxt ( 1998 ) pairs are the best of them...I you want to try a few different pairs of Sovteks with maybe 5 hours on them e-mail me i'll sell the lot cheap to you.........( all un-cryod )