Product Details:

The listed price is the price of two machines (both left and right channels).

1. Analysis of Audio Note Kit One 300B

This is the world-renowned Fantastic Sound 300B single-ended classic circuit of British Anker Company. The circuit part is very mature, the design is simple, the performance is excellent, and the sound effect is excellent. 8th anniversary model (Audiokits Kit1 300B-8). Its appearance is of epoch-making significance. Its sound is thick in bass, delicate in treble, elegant and lively in the midrange, and has a high overall sound density, wide range, rich overtones, and is very durable. As soon as the Kit1 came out, it became one of the most popular vacuum tube amplifiers in the world.

The unique features of this circuit are:

(1) A 100K volume potentiometer is inserted between the voltage amplifier stage and the push stage, which can not only control the gain but also act as the load of the voltage amplifier stage, which plays the dual role of the voltage amplifier stage and the front stage.

(2) The booster stage is composed of double triode 5687 SEPP circuit, its high frequency response is very good, and the distortion decreases significantly as the frequency increases. AUDIO NOTE Kit 1 uses it in the drive stage, mainly considering that this circuit has the characteristics of high input impedance, low output impedance, good frequency characteristics, low distortion, large dynamics, strong driving ability, high resolution, and simple circuit. The 300B with negative gate voltage is a perfect match. Practice has proved that using SRPP circuit as the driving stage can obtain good permeability and air feeling.

【Features】

1. The 300B uses a DC filament for lighting, and a multi-turn precision adjustable potentiometer is used to adjust the balance.

2. Output rated power: 9W*2 (equivalent to 50w+50w transistor power amplifiers! Since all levels of electronic tubes work in a class-A amplification state, the distortion is small, the sound is sweet and soft, and the hearing resistance is extremely high!)

3. The metal film resistors and imported electrolytic capacitors with an accuracy of up to 1% are used. The power filter capacitors use the main capacitors of Japan Chemical Industry and the auxiliary capacitors of Japanese brands.

4. C (capacitor) L (10H 0.3A EI76X45 choke coil) R (resistance) C multi-stage filtering, high signal-to-noise ratio.

5. Using 220W full power low temperature rise power transformer, high-quality H50 annealed silicon steel sheet, and oxygen-free copper enameled wire winding. The 40W copper wire output is made of Japanese Z11 iron core, with strong low frequency and wide frequency response range.

6. The coupling capacitor adopts the German M-CAP MKP capacitor, the sound is very mellow, and the high frequency is thin and transparent!

7. The electronic tube of this machine adopts Dawning 5Z3PA chandelier filament rectifier tube × 1, Dawning 6N8P pre-stage tube × 1, Japan Toshiba 5687 push tube × 1, and Lin Lai 300B power amplifier tube × 1. (The effect of the power amplifier tube will be better if it is replaced by a European and American electronic tube. There are replacement tubes for the three types of electronic tubes.

8. Manual point-to-point soldering, optimized layout, and minimal noise floor. The cathode resistance

and the filament rectifier bridge generate a lot of heat, and a large radiator is also used to dissipate heat to ensure long-term stable operation of the machine.

9. Machine size: width 220MM, depth 385MM (including speaker terminal length), height 240MM (including electronic tube and foot pad height).

12. Net weight of the machine: 15 kg

13. Chassis material: The top plate is a 1.5MM thick mirror stainless steel plate, and the bottom plate is a 1.5MM thick stainless steel plate with a grid, which has good heat dissipation effect. The wooden frame is made of red walnut logs, the thickness of the wood is 20MM, which is sturdy and not easy to

Audio Note Kit 1 main circuit

The circuit of AUDIO NOTE Kit 1 is designed by Jinteng Gongkang. The input stage adopts a common cathode structure with good linearity and high frequency. The double triode 6SN7 with medium u amplification characteristics is selected to amplify the voltage of the input L/R channel. The cathode voltage of the stage is 4.8V, the cathode resistance is 680R, and the current is about 7ma; the signal amplified by the 6SN7 voltage amplifier stage enters the SEPP circuit push stage composed of the low internal resistance double triode 5687 for amplification, and the cathode voltage of the 5687 is 8.4V , the cathode resistance is 820R, the current is about 10ma; after being amplified by the 5687 booster stage, it enters the single-ended power amplifier stage composed of 300B for power amplification, and then pushes the speaker. The cathode voltage of the 300B is 75V, the cathode resistance is 900R, and the current is about 83ma. Under an 8 ohm load, it outputs about 8.2W of power.