Rogue Cronus with KT-90 tubes

Lamcam - I may be wrong but I think that unless you have the Magnum upgrade you can't use the KT 90s - the Magnum version is 90 wpc versus the 55 wpc of the standard model and comes with the KT90s- Double check this with Mark at Rogue.

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

When I received my Magnum it came with NOS Sylvania 12ax7 & 12au7s, sounded pretty good , have since swapped them out for RFT 12AU7s and Tungsol 5751 (12ax7) and prefer the sound - RFTs to me anyway have a more similar sound to RCAs