To get lower distortion and better amplitude-frequency and phase-frequency characteristic, input stage adopts SRPP circuit consisted of 12AT7 and inverter stage adopts constant-current source mode of long-tailed inverter circuit consisted of integrated circuit and 12BH7, which has a more excellent characteristic of AC balance than a typical long-tailed inverter circuit has, also can reduce phase distortion. This inverter stage also has an enough up-dynamic margin that can improve overall system’s no distortionoutput power. Final stage is a power amplifier stage consisted of 6550A/KT88, which can be converted between ultra linearity and triode amplifying mode. Grid employs the mode of fixed bias.

 

 

　    Newly developed output transformer with output power 65W（30Hz）and primary impedance 4.5KΩ, it perfectly matches with 6550A.Both its synthetic technology parameter and sound quality have proved that it can bear comparison with some nowadays well-known output transformers in the world. Its primary inductance runs up to 210H（4.5KΩ 50Hz）and only has a 3.95mH of primary leakage inductance. Primary impedance is exactly flat between 1K—10KHz frequency range and at other frequency range the impedance’s variation is slight as well. This transformer’s power frequency response is 5Hz-150KHz(-3dB), primary resonance frequency 240KHz and distributed capacitance below 100Pf. To ensure the transformer has both high function and quality, best silicon steel material imported from Japanese Nippon Steel is used, and after being stamped out and tempered by the manufacturer, its permeability can be 1.9T. So it is impossible for the silicon steel in general use, Z10 Z11, to be a rival to it. All of these make the transformer have many acoustic advantages, such as deep and high clarity bass, full and stout mid-range, and rigorous and spread high frequency.

 

　    Because No.16.6 was designed rigorously, reasonable settings like terrestrial current distribution, sampling points of loop negative feedback and local negative feedback make the overall system’s open-loop characteristics have a strong performance. Also because the crossfire signal that goes into signal line is well controlled it can eventually perform give out a clear and precise sound quality.

 

　    Considering that tubes’ plate current will change within their lifetime, a digital Ia meter is equipped to help users monitor the working mode of the final stage’s tubes. Practice proves that this function is essential for audiophiles to have.

 

 

　    The toroidal power transformer uses Nippon silicon steel Z11. No.16.6 has a high-voltage time-delay circuit for the moment when it is turned on, choking winding, electron filter and remote controller that is shaped from aluminum.