Cryotone ECC88 tubes from Walthen. Seven tubes. Six pulled from a ZTPre. One tube has some noise occasionally when powering down.  I bought a replacement tube but ran out of time figuring which tube it was.  Approximately 1000 hours. $500 plus free shipping to CONUS
https://wathenspeakers.com/store/p92/Decware_CryoTone_Tube_Bundle_for_ZTPRE_XLR_...
Balanced_Duel_Mono_Don%27s_Pick%21.html