Few years ago, when I was in ShenZhen, China, I saw 6p3p and was attracted by its 2A3 type bottle shape. I purchased a few pairs just for fun. After I had checked it's data sheet, I found that this 6p3p is actually similar to 6L6G. I order 24 pairs from the same supplier to make kit set for local market. All of them also marked "J" means military grade, and it's really cheap, about USD$5.00 per piece.
I had designed a simple SE amplifier and put it together to see how it sounds. After some tweaking and tuning, I found that its sounds sweeter than the EH 6L6GC. Power output is around 6.5W at 280V supply. I re-adjust the bias to lower power output, around 5W before clipping, so that I can use my smaller output trannies for my kit-set. Although I had sold out all my 6P3P kit-set at USD270 per set, about years ago, I put this article just for people who wish to know more about it.
Again, I'm using 12AT7 as driver, not because of I love 12AT7 a lot. I have a lot of them in my store room. Furthermore, I don't want high gain like 12AX7 and then using lots of feedback to spoil the sound quality.12AU7 can't give me enough gain for this design so 12AT7 is the one I'm using. Plate resistor is 22K ,slightly lower than 12AT7 like to take, but it sound better compare to higher value. I believe that any tetrode or penthode need to apply slight feedback for better damping factor and performance. I apply a bit of feedback in this design. The output trannies is in bottom of my chassis, I found Dacware's kitset have similar chassis layout as mine after I sold all of them, that's why my layout of 6c45, 832,1626 etc is differ with this design. I don't want to be a copy-cat!
The photo shown here is the kit set that I had sold out, I keep 1 set just for future comparison or reference. Single ended looks simple to build, most of my previous customers can build one without or slight problem. I'm planning to get another carton of 6p3p for local market, will be available soon on my parts/surplus page.
Schematic can be download here.