Power Tubes for Rogue Cronus Magnum?

I have a regular Cronus which I like a lot. It sounds really good with the EL34/6CA7/KT66/6L6 family of tubes. Not so good with 6550s.

According to Mark at Rogue the power supply and other upgrades in the Magnum edition match better with the 6550/KT88 family. It would be nice to be able to have that extra power at times. But I really like the sound of the Black Treasure 6CA7s and Genalex KT66s I use and want to know that they will still sound great in a Magnum before I upgrade.

So, has anyone with the Magnum used these tubes (or other EL34/KT66s) and how do they sound?

And how do they compare with whatever KT88/90/6550s you're using?


Have you ever tried Svetlana Winged "C"? Those were the KT88 I'd prefered when I had an integrated amplifier with that kind of tubes.
No, I haven't, but I'm looking for feedback from those who have used EL34/KT66 variants in a Cronus Magnum.
Unless they've changed the top cover plate of the Magnum the power tube holes are not big enough for KT88s , they are either for the EL34 types or the higher power KT90, mine is 2 years old and that's the way it is with this. The KT90 to my ears is not warm like some KT88s I've have/had in other amps
Thanks Facten for your response: that is helpful info about the KT90.

There is a way to use KT88s, or other wide bottle power tubes in the Cronus: socket extenders. I use them now in order to employ 6CA7s and KT66s.
wasn't aware of those - any negative effect from having them in between?
None that I could hear.
Hello everyone, I'm new to the site and recently purchased a cronus magnum and wanted to know where I can purchase a set of 'socket extenders' that Rpf mentioned. Also can the KT 120's be used if the sockets are in fact extended?
might try tubemonger.com for extenders

suggest talking with Mark at Rogue directly re the KT 120s
Thanks Facten. I did find the extenders on both tubemonger and tubedepot. Also I spoke with Mark @ Rogue and he has told me that rolling KT120's is ok and will present no problems electrically for the cronus magnum. So the only issue remaining is clearance through the top cover of the unit.

I'll post back in a few weeks after a proper break in period. My current set up:

Rogue Cronus Magnum
Vandersteen 3A Sigs
Rega Saturn
Audioquest Rocket 33