Henry SEID "High Fortune Sound" 1997 07
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In a set of perfect sounds, the signal from the CD machine output is the first step, and the prefame is also an important ring. In view of all kinds of conditions, I used the ECC32 for the previous stage, due to the Direct IntelectroDe-Capacitances, and the Miller Effect also decreased.
In the workshop, the ECC32 is mostly used for SRPP. The advantage is that the production is low, narrower, for breakthrough, on the line, using a first-class amplifier, first-level buffer. As shown in Figure 1. Buffer uses Double-Cathode Follower. Basic conditions in the production: When the maximum output is within the maximum output, the dynamic characteristics of the input and output should remain linear. In other words, the harmonics and intermodulated distortion rates are low, and the frequency response at 5 Hz-30kHz is straight.
On the line structure, V1 uses half ECC32 as the first stage voltage amplifier, and its cathode resistance does not have a bypass capacitor, there is current negative feedback. The calculation of screen resistance and cathode resistance, its equation is as follows: Screen resistance = (300V-112.5V) /13mA=14.42 (kΩ) Cathode resistance = 4V / 9MA = 444 (Ω)
Basically, the first level amplifier cannot be distorted. Because it will directly affect the subordinate work, the so-called one child is full. V2 is used as a cathode coupler, for breakthrough, this buffer is used as a Double-Cathode Follower. This time Double-Cathode-Follower is a shadow of Active Load. It is the advantage of output impedance than the ordinary buffer is 11/12, which is better than the dynamic and characteristics of the general buffer. Master the ability, convenient Match any model.
A stable power supply is important to the pre-order, this time the regulator structure in one generation of MFA is used, which can be divided into one-stage constant current amplifier and regulator portion, as shown in Figure 2. The filament is also very important. I used a 6A power transformer and 60000μF capacitance, and the regulator used LM338K (see Figure 2), which is the general LM317T, 7805, etc. 5A, and 80dB Ripple Rejection and low internal resistance, there is short-circuit protection in input and output. Be
On the production, the body is used to use brass, which makes it impartn by its physical factors, and uses the C-C-Core power transformer in the high voltage power supply to seek the efficiency high and the internal resistance of the power supply, then use two chokes. Circle, there is a regulated portion therein. In addition, on the line, in order to improve the sound quality, the resistance is used for A & B resistance, and the screen is resistant to the unoccupied resistance of RS, and the transportation capacitor will depend on its own taste, its numerical value is (0.68μF ~ 1.5μF) . On the delivery capacitor, I used Sprague-Black Beauty, Dubilier-Black Cat, Gudeman, WEST-CAP's LμF, where West Cap, Gudeman's voice is the most rare, high and low analysis. And I am standing around the regulation, and uses the CVL81 in 1961.
In the adjuster, the first magnitude, the voltage is 300V, the current is 8mA, the cathode voltage is 4V, and in the buffer, it is 300V. Will do your friends, may not be stressed first, then install it. In the audition, I think the former fully demonstrates its arrogance, the bass is strong, the people are warm, and the latter has highlighted transparent, the appearance is first-class, its bandwidth is 5Hz ~ 500kHz, everyone may wish to do it.
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