WhitakerAudio 60 W Stereo Power Amplifier, Руководство пользователя и по сборке, Страница: 119 / 154

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60 W Stereo Power Amplifier
10.1.3 5U4
The 5U4 is an octal tube type used in power supplies for a variety of products having high dc
requirements. The pin layout is shown in Figure 10.5.
Vertical mounting is preferred, but horizontal mounting is permissible if pins 2 and 4 are in
the vertical plane. The voltage at the filament terminals should be 5 V at an average line voltage
of 120 V. It is especially important that this tube, like other power-handling tubes, be adequately
ventilated. Typical rating chart is shown in Figure 10.6.
Selected tube parameters are listed in Table 10.4.
Peak AF grid #1 to grid #1 voltage 68 V
Zero signal cathode current 134 mA
Maximum signal cathode current 155 mA
Effective load resistance (plate to plate) 8000
Ω
Maximum signal output 24 W
Note:
1 Obtained from taps on the primary winding of the output transformer. The taps are located on each side
of the center tap (B+) so as to apply 50% of the plate signal voltage to grid #2 of each output tube.
Table 10.2 Key Parameters of the 7027A
Legend:
H = heater
P = plate (1, 2)
NC = not connected
H
H
NC
P1
1
2
3
4 5
6
7
8
NC
NC P2
NC
Figure 10.5 Terminal connections for the 5U4.
Type 5U4GB
Heater = 5 V ac
Maximum operating values with:
AC plate supply voltage (rms) per plate (without load)
0 100 200 300 400 500 600
DC output milliamperes per plate
200
150
100
50
Capacitor-input filter
Choke-input filter
Figure 10.6 5U4 rating chart.