The project is moving along well. After evaluation by my local master players, it was determined that the amp lacks gain and mid-range response. I have addressed the gain issue using a single triode stage of post tone control amplification. Now the 6L6 can be driven to full output. I still see the distorted sinewave and believe that is the reason for the loss of mid range. So, the next task is to correct the output waveform. That may be a function of bias, or the final stage design. The pre-amp sinewave is picture perfect. In part 5 I will experiment with the current bias configuration. If that does not cooperate, I will install a negative bias circuit to see that difference. This has been a big fun project. Hopefully in the end we have a cool 6L6 head that someone out there will enjoy. If you want a copy of the newest schematic, just send me an e-mail. I have it saved as a .jpg file. As stated before, this is an evolving project, hold your criticism as it changes as we go along. I am open to your suggestions. Lets have fun with this project! TD
