New tubes in Rogue M-180 Monoblocks

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.

"08-29-12: Tobes

That seems like very poor longevity/reliability from the KT90 tubes - unless you're running the amps 24/7?"

The amps do get heavy use from morning until evening every day. But I also forgot to mention that the KT-90s were biased at 40 mA as per the manual. When I called Rogue to ask about the KT-120s, they said that their new recommendation was 35 mA, and that's what I've had the KT-120s at since I installed them.

I no longer have a full complement of KT-90s, so I can't do a re-evaluation of them. But I've never felt dissatisfied with the KT-120s.