Heyun M100 integrated tube power amplifier

Judging from the circuit of Ml00, it is a typical tube circuit. Its pre-amplification and post-input stage amplification are ordinary
common cathode amplifiers, the long-tail inverting stage, and the final power amplification are an improved standard connection method. However, when
building an ordinary circuit, the circuit parameters must be carefully selected and adjusted according to the test indicators and subjective listening requirements.
First of all , it is the open-loop characteristics of the whole machine, and the open-loop gain design of the Ml00 rear stage. It is relatively low. The input stage uses a low internal resistance, low noise and high
transconductance tube 6N11. The open-loop frequency response, distortion and other indicators are relatively ideal. This also creates conditions for applying shallow large-loop negative
feedback The change in the negative feedback amount of Mloo's large loop has an important impact on the sound tendency. 6
The negative feedback amount of Ml00's large loop is only 5.8dB. The impact at low closed loop is 6Hz~60kHz (-3dB), and the harmonic distortion is at 10W.
The shallow amount of negative feedback at 0.15% (1kHz, 10kHz) also brings some characteristics of the sound; it is clear, elastic, rich and clear bass
, good transient response, and the midrange also responds more profoundly.