LG97 12AX7+12SN7 push-pull circuit boards for 300B, 2A3: imitating GOLDOX brand GOX-300B/2A3 tube amplifier general push-pull circuit, classic circuit.
High-quality glass fiber double panel (240×110mm, thickness of 2mm is not easy to be deformed), dual monophonic symmetrical design. One 12AX7 left and right channel amplification, two 12SN7 left and right inverted push-pull outputs. Selected high-quality component assembly, high-quality ceramic silver-plated tube socket, 1～3W metal film copper foot resistor, and the resistance wattage is left in reserve. Phi lips 22μ400V electrolytic pre-stage filter, ruby cathode electrolysis, West Germany WIMA Red Weimar coupling capacitor. Due to the reasonable wiring, although all the filaments are powered by AC, the hum is very small, and the amplifier has more flavor.
Can be installed in a closed case or with exposed pipes. The circuit is mature, excellent performance, reasonable wiring design, universal component size design, voltage and component parameters marked on the board, simple assembly, as long as the wiring is correct, it can be a one-time success, it is a shortcut to success, suitable for DIY production.
This circuit board can use 6N8P to directly replace the 12SN7 tube, and the filament can be powered by 6.3V, and the others do not need to be modified.
This circuit has strong driving force and can be easily pushed for 2A3, 300B tubes with deep negative pressure of low μ gate. It is also suitable for 6550, KT88, KT100, EL34, 6L6G, 6P3P, 6P6P and other tubes.
This circuit board can be powered by 12AX7 and 6N8P tubes and filament 6.3V.
Board features: 12AX7 and 12SN7 are both 12.6V power supply. The 8-pin socket and the 9-pin socket are designed for flat and round sockets. The flat sockets are suitable for general-purpose sockets, and the round sockets are suitable for CMC extra-high-grade Teflon or ceramic bakelite sockets.
The circuit board pushes 300B, 2A3 electron tubes, and adopts fixed grid negative pressure control, as shown in the figure below, for reference only!
Note: The 300B or 2A3 tube is not on the circuit board, and the power circuit, fixed grid negative voltage circuit, potentiometer, etc. are not on the circuit board. When installing the matching Taurus case, you need to match the two electrolytic reverse sides on the board.
Line characteristics: The sound is generous and relaxed, and full of boldness.
This circuit board can use 6N8P to directly replace the 12SN7 tube, and the filament can be powered by 6.3V, and other changes are not required.
The complete circuit is shown below!
Affirm: West German WIMA red horse on the circuit board is a second-hand disassembled product. The types, brands, models and specifications of some components are slightly different due to the different assembly batches of the components on the finished board. If the color picture and parameters of the components on the finished board are different from the physical and schematic diagrams, the components and parameters on the received board shall prevail! Finished boards are tested and sold normally.
