1. This is a truly integrated amplifier with front stage. The front stage is composed of pentode EF183, and the rear stage is amplified by 6N8P two-stage voltage, plus 300B
   Amplify the output.
   The 300B itself has no negative feedback. The working point is 400V, 80mA. The powerful drive allows the 300B to work in the A2 state. The cathode uses a constant current source to stabilize the working point. You can change any 300B tube at will without any adjustment.
    
   All AC filaments, Lao Cao's new generation AC filament module, the output noise prototype A is measured to be less than 0.2mV. 20HZ-20KHZ broadband noise is about 0.6mV. The filament adopts a slow-start circuit to avoid the impact of high current when the filament is turned on. In theory, the life of the filament is more than 2 times longer.
    
   Using large output cattle, EI type 114 stacked 50 thick HiB iron core, the maximum undistorted power reaches 14W (8 ohms, 1KHZ, 10% distortion), and the 10W output distortion of the measured prototype is about 4%.
    
   4 sets of audio input, relay switch.
    
   60 levels of volume switch, each level is 1dB. The front stage has 6 gears, each gear is 12dB, between the front and rear stages, 12 gears, each gear is 1dB. ALPS's 6-step step switch and 12-step pure copper step switch custom-made by Taiwanese-funded factories are all on first and then off structure, no switching noise, long life, and perfect solution to all the problems of band switches.
    
   This machine is probably the most complicated 300B single-ended power amplifier. 4 sets of high-voltage power supplies, two sets of filaments, and a meter drive circuit.
    
   This machine is characterized by comprehensiveness and balance. In addition to maintaining the original transparency, naturalness and delicateness of the 300B, it has quite good control and low-frequency diving.
    
    
    
    
   Technical parameters of the whole machine:
   1. Four groups of RCA inputs
   2. Output: 4Ω, 8Ω (16Ω, 8Ω, or other impedance can be customized)
   3. Maximum output power:
                        14W×2 (8Ω, 1KHZ, 10% distortion)
    
   4. Frequency response: 20HZ-20KHZ -0.4dB (8Ω, 1W)
   5. Output noise: <0.8mV (20HZ-20KHZ broadband)
                           <0.2mV (A weighting)
   8. Machine size: 430×390×220mm (width, depth, height)
   9. Net weight: 25.5KG
    
    
   Measured parameters:
    
   1, 1W power frequency response:

2: Output power VS distortion: (8Ω, 1KHZ)

2：

3: A-weighted output noise: