LG249 tube 6N9P+6N8P×2 1W+1W small power amplifier board/headphone amplifier board:
6N8P 6N9P These two bile ducts, no one knows about tube amps. The 6N8P's high current, medium μ value, and low internal resistance (7kΩ) characteristics are widely used in audio amplifiers and have a pivotal position in the amplifier industry. The 6N8P has a relatively thicker sound due to its higher operating voltage and higher operating current. The middle μ value and low internal resistance make it stable. 6N8P is a multi-purpose dual triode. The two internal triodes are completely independent except for the filament. They have good symmetry and are suitable for phase inversion, excitation and resistance-capacitance coupling amplifiers. The tube has good linearity and little nonlinear distortion. There are many types of 6N8P similar tubes in the world, the European and American model is 6SN7GT, and the former Soviet Union model is 6H8C. There are mainly two types of 6N8P produced in my country: Shuguang and Nanjing. Nanjing's 6H8C is especially popular with enthusiasts. 6N8P has a large stock, cheap, and easy to buy. It is a cheap and good-quality sound tube.
6N8P 6N9P has good linearity, and the same is a big eight-pin tube, with 6N8P parallel output, pushing 5.5K to 10K single-ended output can achieve 1W power.
Double-sided glass fiber board (219×101mm), the resistance and capacitance components can be installed on the front and back, and the pipes and sockets are exposed to install (the pins are marked on the board, please pay attention to the pipe sockets during assembly). Imported RC component assembly, 1A/1000V diode rectification, Philips electrolysis 33UF/450V×4 + choke filter, German "SIEMENS" Siemens EPCOS 10U/450V electrolysis×2 decoupling, 4 German WIMA 0.22μ/250V Capacitive coupling, three silver-plated ceramic sockets, filament AC power supply. Connect the power transformer, output transformer, and speaker to work.
Matching transformer; high voltage 230V 30mA, also suitable for dual voltage, welding two diodes on the board to become full wave rectifier. The filament is 6.3V0.8A for two 6N8P, 3.15V～0～3.15V 0.3A for one 6N9P.
There is a choke coil interface on the board, and the choke coil needs to be connected outside the board to enhance the filtering effect.
LG249 finished board is installed including three tubes, excluding choke
LG249 finished board reverse installation including three tubes, excluding choke
LG249 finished board is not equipped with tube choke
LG249 finished board reverse installation without tube choke
Board code: LG249 The matching electron tube is a domestic stock second-hand tube
The three electronics on the circuit board are all big octa-pin tubes, and you can also use imported 12SL7 and 12SN7, 12SL7 and 6N9P are the same, 12SN7 and 6N8P are the same, the two are interchangeable, but the filament voltage is 12.6V.
The sound of the power amplifier board is fine and smooth, the sound is sweet, warm, soft and balanced, the sound field is open, and the sound is transparent and full.
The disadvantage of this power amplifier board is that the power is only 1W+1W, which is only suitable for headphones or high-sensitivity speakers with large-caliber paper cones, and not suitable for low-sensitivity speakers such as small-caliber leather/foam edges.
Matching 28W power transformer, EI 66X35mm Z11 material, Red Bull Bracket has strong adaptability and can be placed horizontally and vertically. Input 220V alternating current, output 230V40mA, filament 6.3V1A, 3.15V-0-3.15V 1A.
Affirmation: The components on the finished board are of different assembly batches and the board colors are different. The types, brands, models, specifications and parameters of some components will be slightly different. The components and parameters assembled on the received board shall prevail! Some components on the circuit board are second-hand disassembled products, and the finished boards are tested and sold normally.
