EL34 push pull schematic converted to s stereo design with organized resistors. Lots of routing but worth the ease of install. HIGH VOLTAGE, do not attempt this project is you are a novice. You'll lose a finger or two and be broke by the time you get any sound. The 6n2 switch requires strapping the B filament in the middle of the board to ground as well. That's because it will still be connected to pin 9 on the 6n2s which is grounded. Bias is controlled in 3 ways: negative V to grid 1, negative v to grid 2, and balance between the cathodes. Feedback is 16 ohm recommended and there is addition resistance to tune it. 300VDC, 360VDC MAX (0.75mm copper in the layers), 6.3V + 6.3V + 6.3V - do not combine the center filaments for the driver tubes with the power tubes. -70VDC bias voltage. 40ma = 400mv at the testing points.