Questions on KT150 tubes

KT150s are amazing sounding tubes, and after replacing my nearly 3 year old KT120s (they served with distinction as I work 'em fairly hard) about 12 months ago I have to say they don't make me want to ever use anything else in this amp (I have KT88s and 6550s that patiently stand by and also sound fine, but the 150s just work))…big sound, more effortless power (seemingly)…I bias at the amp's recommended 500mv point and they just stay there…large glass power pickles.

Ditto with what the "Wolfman" says. I have KT-150s in my ARC Ref 150 SE. When listening to music selections that I hadn't heard in a while (pre-KT-150), I am amazed by the difference.

Yes ... they are expensive, but ARC tells me that the KT-150s should last 50% longer than the KT-120s (3000+ hours as compared to 2000 hours).

What sonic differences do you hear in the KT-150s compared to the KT-120s? I have been running KT-120s in my Emotive Audio amps for a couple years but no tubes last for ever. When replacement time rolls around, I am wondering what to expect if I get 150s instead.

I have the same Jolida amp as the Wolf_Garcia. I had the Tung Sol KT-120s and later got to KT-150s. To me with the Tung Sol KT-150s in place I've got the big and sweet midrange/highs of an EL34 tube with so much for oomph bass wise. The bass wasn't boomy either like when I had JJ-KT88s in my amp. To me when I had the Tung Sol KT-120 in my Jolida I found the music to be ok sounding not a good experience like the Wolfman had. I ended up getting NOS GE 6550 tubes in the Jolida and liking that sound. When one of those tubes blew up on me I then went for the KT-150s after having long talks with Jolida techs to ensure the amp would survive.

My KT150s have been in my amp long enough to erase the  memory of the tubes preceding them.