Cayin A-805 300B & 805 HIFI Single-end Class A Power Amplifier & integrated AMP 50W*2

Feature:
1. A-805 has 4 sets of RCA inputs, 1 of which is the pre-amp input, which can be used as the back-end.
2. A-805 uses 300B bile duct to push 805 bile duct, the sound can not only maintain the warm and soft characteristics of 300B and sweet tone, but also retain the characteristics of 805's strong driving ability, large dynamic range and thick sound bottom. The single-ended amplifier in the pure class A state of the 805 has a large output power of 50W. Compared with the push-pull and other amplification methods, the even harmonics generated by it are not cancelled out, and the sound is more natural and full.
3. 805A tube as final output
4. 300B is push tube
5. 6SN7 as input amplifier tube
6. A-805 uses EI type output transformer with high efficiency and wide frequency response, and determines the optimal air gap size of the transformer. The output transformer plays a very good role in flexible cross-connection, so it can adapt to the nonlinear impedance change of the speaker unit to a certain extent, making the speaker easier to push. Both the power transformer and the output transformer are packaged in a metal shielding box to avoid interference to the circuit as much as possible
7. A-805 is still made by hand. The whole machine is welded by scaffolding. The components selected are the result of repeated tuning by the designer. The voltage amplifier stage uses a customized 6SN7 tube, the push tube also uses a customized 300B tube, and the 805 tube of the single-tube single-ended class A amplifier is also a customized product according to Spark's requirements.
8. The NFB button on the panel is the feedback selection button. A-805 has two feedback selection functions, and can also be used as a pure power stage. In addition, it has external 805 tube current adjustment (BIAS ADJUSTMENT), monitoring table (BIAS) and hum adjustment (HUM BALANCE) functions. In order to prolong the service life of the tube, A-805 is equipped with a soft-start delay function. When the filament is fully preheated, the working power is gently turned on, which effectively protects the negative impact on the tube during startup and preheating. A-805 also has a remote control function, which can perform basic operations and is very convenient to use. Remote control for volume adjustment, source selection and mute operation of the machine

technical parameter :
Rated output power: 50W+50W
Overall frequency response: 18Hz-28kHz (-3dB)
Total harmonic distortion: 0.5% (1W/1kHz; less than 10% at rated power)
Signal-to-noise ratio: 95dB (A-weighted)
Input sensitivity: 300mV (when combined input); 1300mV (when pure power input)
Input Impedance: 100kΩ
Output impedance: 4Ω, 8Ω
Input terminal: three groups of RCA; one group of PRE-IN
Tubes used: 6SN7×2, 300B×2, 805A×2
Overall volume: 420×389×240mm
Net weight: 37.8kg

1: Power switch

2: Volume control knob

3: NFB. Negative feedback state selection button

4: Input select button