New tubes in Rogue M-180 Monoblocks


I understand the M-180s now ship with the KT-120 power tubes, instead of the KT-80. You can also simply replace the KT-80 with the KT-120 if you already own these amps. I'm curious whether anyone has done it and what their impressions are as far as the difference in sound. Is the over $300 upgrade worth it?
actusreus
I've been running KT-120s in my M-180s for about 6 months. I'm still using the 12A*7 tubes that the amps shipped with.

Yes, I'd say it's worth it. My comments at the time I did the replacement were:

"They just give you more of everything: more treble, more colors, more drama. As happy as I was with the original sound of the Rogues, I always wanted a bit more texture and warmth on massed strings, and the KT-120s give you that."

Also, from what I've read, the KT-120 is a more robust tube than the KT-90. Depending on usage, I'd expect to have to replace 1-2 KT-90s a year (and a fuse blows when the tube blows). I haven't had a KT-120 blow yet, but only more time will tell.
08-29-12: Daverz
Also, from what I've read, the KT-120 is a more robust tube than the KT-90. Depending on usage, I'd expect to have to replace 1-2 KT-90s a year (and a fuse blows when the tube blows). I haven't had a KT-120 blow yet, but only more time will tell.

That seems like very poor longevity/reliability from the KT90 tubes - unless you're running the amps 24/7?
I bought my ARC amp S/H and I'm still using the same output tubes (SED winged C 6550) after 2 years. ARC tend to run tubes on a pretty rich bias too.
I'll chime in and completely agree with Daverz but add that there seems to be more lower end punch as well with the KT-120 tubes. Highly recommended if your amps can handle them.
Just curious, but I have had a few people tell me that the "sparkle" of the 120 tube seems to wear off a bit after listening to them for a while. Sort of like the new car smell going away after driving your car for a few months. And that the 120s can be a bit harsh. They all went back to 90's after trying them.

I take it most of you are not getting this?

I've not tried any 120's in my demo gear here. I may need to just purchase a few and see how it goes.
I can say that my experience with KT-90s was not good , either. They didn't last long at all and when one blew it took out a resistor, burned a wire, and a fuse, in the amp I was using- not a Rogue. It was enough to keep me away from them more or less permanently. I am curious about the KT-120 and will ask Jadis if I can use it in the DA-60. I have a feeling they won't endorse it.The trannys on a DA 60 are big and probably could manage it but repairs on an older Jadis are Tre Expensive.