Over the weekend I spent a few hours trying to eliminate the last of the signal noise on the Shure M65 clone. I added shielding to all of the input and output wiring and grounded the shielding back to the chassis ground point.
Much to my dismay after adding the grounded shielding around the I/O wires the signal noise actually got significantly worse! It was so bad that I'd deem it unusable. After doing some testing with decoupling the ground and trying some different chassis ground points I discovered that improving the ground connection from the chassis to the outlet ground by re-crimping then ground lug and removing the grounding wires from the I/O shielding was what it took to remove all the noise. It's been a long journey but I now consider the electronics finished! Next up will be completing the casement using 3D printed edge rails and acrylic panels. I plan to leave the sides and top transparent so that the electronics can be displayed and to install a removable top to make re-tubing easy. Here's the finished electronics as they stand!
As part of the finish work I also installed the upgraded Electro-Harmonix Gold 12AX7s. They are a properly matched set and have almost 12db more gain than the outgoing JJs! I am super pumped to move on to the next electronics project which will be an input switcher with an integrated preamp stage and a level meter VFD. Stay tuned for more progress on moving to an all analog listening room!