So, after having a good experience with my Motorola EL84 SE, I decided to deconstruct the Mr. Liang's KT88 and use the components to build a new SE amplifier. The parts that I could use were the Jensen coupling capacitors, Jensen electrolytic capacitors, some 6DJ8s, EL34s, KT88s, 6L6s, ALPS potentiometer, RMG resistors, etc.
I then bought a pair of 20W EI 2.5K / 3.5K local Hong Kong made single-ended output transformers, an EI power transformer and a Chinese made chassis. That was my second SE amplifier with no negative feedback. I tried using paralleled 12AX7, 1/2 12AT7, 1/2 6DJ8, 6C45PI to drive the power tube including KT88, EL34 and 6L6.
The results were not very satisfactory. Then, I swapped the pair of trannies with a pair made by a Chinese tranny guru. Since then, I started to realize how important the role of the trannies is in a tube amplifier. The difference was so obvious that the machine sounded completely different! What an open sound stage that was.
At that moment, I was using the 6C45PI with a lot of driving current. The only thing that I didn't satisfied was the dynamic.
Therefore, I started thinking maybe one stage of amplification was just not enough to drive the power tube good. With this idea in mind, I changed the driver stage from one to two, using 1/2 6DJ8 to drive 1/2 6CG7 and then coupling to the power tube. And the result was just good. And that is the circuit I'm still using at the moment to drive my pair of Klipsch Heresy. And the power tube that I like most in this machine is KT88.
I got two pair of 6B4Gs in hand and the project would start in the near future. I have quite high hope towards 6B4G.