I'd check again about the standard versions use of KT 90s - see below from their site re Magnum upgrade
from Rogue site - for Cronus which is in Titan series
The Rogue Audio "Titan MAGNUM" Series
The "MAGNUM" versions of the Titan series features significant parts upgrades that improve performance in your Atlas, Metis or Cronus in a number of important ways. Increased transparency, greater dynamics, improved bass and high frequency response, as well as a smoother and more refined presentation are all part of the Magnum upgrade. The extensive power supply mods permit the use of the KT90 power tube which increases the rated output power of the Atlas and Cronus to 90WPC!
The Magnum package consist of the following modifications:
Atlas and Cronus Magnum:
- Larger power supply
- Power supply mods
- Polypropylene bypass capacitors
- Precision Dale-Vishay resistors in critical spots
- Upgraded binding posts
- Gold tube sockets
- Upgraded small signal tubes
- KT90 output tubes
- Magnum logo on faceplate