Rogue Cronus Magnum 2 tube rolling

Nope, waste of money.  Tried it on my Cronus Magnum 1.

It is always nice to have a spare set of tubes available to diagnose possible issues with any piece of tube gear, with that said go ahead and get a set for the 12au7 spots in your preamp and I would recommend the Psvane T Series Mark III Premium tubes at about $75.00 a pair, I run a pair in my Lamm LL2.1 preamp and my Jadis tube dac also run the 12 at7s in my VTL amps and the 12ax7 in a ASL headphone amp. I have had nothing but good things to say about the Psvane premium tubes and have settled on them over all the NOS tubes I have tried and have become my go to tubes. Good luck.

We a friend did a test of 12au7's, about 8 different ones.  Psvane were not near the top.
Mullard won, GE second.  Both NOS.
Personally I'm using Philips JAN and RCA in my amp.

Agree with the NOS Mullards. Have them in my Rogue Pharaoh. Wow, what an improvement in sound. The GE's could be re-branded Mullards. Check to see if the tube says Made In Gr. Britain. The tubes in my Pharaoh are 12au7's. People's preferences seem to go with the type of tonality they prefer with these NOS tubes.

elevick, just one question if Millard and GE won your shoot out why are you running JAN Phillips and RCA, in my system I run what is best and those are the Psvane.

The JAN Philips I have are a better match with my current Grommes Monoblocks.  Every amp is different.  If I had to blindly pick a brand and only 1 brand, it would be Mullards.  The other reason for the JAN is power handling.  My Grommes really push the voltage limits and already ate a quad of RCA's.  The JAN's are happy running at higher voltages.

The Mullards are my favorite tube as well.

The 12AU7 driver tubes make a larger difference in sound than do the 12AX7 phase splitters in my experience and according to Mark O'Brien of Rogue. 

My preference is for NOS Mullard CV4003s. I use an RT 6189 in the pre-amp spot and either NOS Mullards or RCA black-plates in the phase splitter positions.

Funny how we got different answers from Rogue. I was told that the 12au7 driver tubes made the else impact.   In anycase, unfortunately I sold the CM2 and bought a solid state amp.