Thank you for your interest in my vacuum tube based circuits: DG300B, Novar Spud, 6LU8 Spud, and Universal Filament Regulator. Due to the dwindling sales of these circuits, and to my efforts to position Neurochrome as a state-of-the-art solid-state DIY circuit manufacturer and vendor, I have decided to discontinue my vacuum tube circuits. I have no circuit boards left for the DG300B, Novar Spud, 6LU8 Spud, or Universal Filament Regulator.
The only vacuum tube related circuit remaining in my portfolio is the 21st Century Maida Regulator. I expect it to remain as part of my portfolio for years to come.