The second version is changed with putting the pre-amplifier 12AX7 and output to 6BQ5, or EL84 5+5 Walt. I like the sound for this version, however the power of output sound still not enough for me, I try to have the third version, it is using the single end EL34 or 6CA7 10 +10 Walt. Wow, the component is very high cost, my girl friend was keep on nagging the price when I brought it.
If you are interested in this project, can download the PCB file and more specification documents about output Transformer and make by yourself.
For tube amplifier now I have stop the study as it cost to high. Also it is very high temperature and heavy due to the big transformer and tube glass easily break. However, I do remember the sound with tube amplifier is very nice. Below it is the tube amplifier done by me.
Sorry Tube Ampilfiers, discontinous