Raising the thread from the dead.
I am a proud owner of B7 with R2R upgrade in place, with superclock and DSD 512 upgrade planned for future. I recently picked up matched pair of JAN CRC 1945 WWII 5R4GY and looking for output tube recommendations (would like to keep the cost under 250 for the pair if possible). I have a pair of ElectroHarmonix 300B Gold tubes that I am going to roll into the DAC with the JAN rectifier instead of the existing PSvane 101d and Shugang 274b.
I have gone through this thread, the one on Whatsbestforum and Audioshark about tube rolling in B7. What I am finding is that the px4, px25, kr242, tak 300b, elrog 300b, Lampi eml 45 are the top output tubes with Tak 274b and WE 274b as the rectifier of choice. The prices on those tubes are out of question so what is the next tier down.