Kt120 Vs kt90 Sound characteristics

If you wish for good bass, smooth highs and a rich midrange, try KT77s. I auditioned the Cronus Magnum 3 at home with the stock KT120 and found them a bit clinical also. So I ordered the amp with Gold Lion KT77s installed from Rogue. If you choose KT77s you’ll need to reduce the bias from 35 to 30 as per Rogue.

The KT 120 tubes in the Cronus Magnum gave an authoritative sound but there was always a bit of grain in the background which I did not get with EL34’s. At the time, only Tung Sol made the KT120  tubes but there may be other manufacturers now.  I didn’t care for them.  I sold the amp after a year and a half as it wasn’t what I thought it would be.  I was disappointed.  I wanted a more lush midrange with better bass and no grain. 

@stereo5 I’m an ex EL34 diehard myself. Over time learned Tung Sol KT120s can sound really good with at least two factors present. Lesson learned here before making premature judgement. Burn-em in at least 200+ hours, no joke. They DO settle in nicely, same with my KT150s changed at 300hrs. I learned this from Conrad Johnson owners too. Today I run KT120s today in my mono amps. The second is a game changer for digital front-ends. Making sure a really good digital source/dac is used along with a clean and quiet power supply. I like the sound better than my former EL34 amps now. As for KT90s, I won’t digress, there are several reviews indicating few amps run KT90s well, and most moved on to KT120s anyhow. My KT150s sit in their boxes. KT120s can sound good, given a fair chance in well designed amplifiers, good transformers, caps, bits inside.  

@decooney,

I get what you are saying but I used that integrated with the KT120’s for over a year at 8 hours a day.  Surely the tubes would have been very well broken in.  Perhaps it was the Rogue Integrated itself that was introducing the noise.  It was the first gen of the Cronus Magnum that I bought used.  Maybe the second and third generation was better?

Which KT90, the Electro Harmonix? In the Rogue tube amps, EH KT90 has more treble energy while being leaner through the midrange and bass compared to Tung-Sol KT120. I think almost everyone prefers the KT120, unless you have a particularly dark system that needs the extra zing up top. 

KT120 have excellent warmth, body, and bass impact. Great for rock. They have a bit of "sweetness" to them, but not as much as you'd expect from say EL34. You may or may not find preference with Gold Lion KT88, which have extra airiness and refinement to them, and slightly sweeter midrange, compared to KT120.