Han her er ihvertfall glad i 6L6
http://www.6moons.com/audioreviews/dared3/vp20.html
For some hard-to-explain reasons (but I'll try my best regardless), I prefer the 6L6 to KT88s and EL34s. Though these tubes are all associated with guitar amps for their ability to handle heavy loads and forge beefy output power, the 6L6 to me seems to have a more linear, wider bandwidth and to pack more punch and bounce. It's particularly noticeable when playing back piano recordings. This same punch and bounce transmutes into breathtaking attacks and exploding air molecules discharging from hammers and strings rebounding off the sound board. Not only that, the high-to-mid frequencies seem sweeter and richer, the mids-to-lows more potent and clean, the lowest bottom end permeated with pathos. In short, it sounds just like a musical instrument. Once a concert pianist friend of mine came over when I had the VP-20 playing some Rachmaninov Ampico recordings realized on a modern Estonia concert grand. She thought my wife was practicing (our piano happens to be an Estonia). That's how convincing the piano could be on the VP-20, perhaps more so than over my other Dared amps. And that was just using the stock Shuguang tubes. In fact, it's not just with the piano. For me, the 6L6 is the best all-around tube for any kind of music, with wide dynamic range, rock-solid bass, crystal clear highs and plenty of headroom in terms of energy. It might lack the richness of the KT88 or the midrange magic of the EL34 and certainly won't compete with 300Bs and 2A3s for that warm honey-dew coloration. Yet if I could have only one tube amp, I will take one with 6L6s without the slightest hesitation.