WhitakerAudio 60 W Stereo Power Amplifier, Руководство пользователя и по сборке

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60 W Stereo Power Amplifier
46) Check the right channel amplifier and then check the left channel amplifier. It is normal to
observe small differences between readings for each amplifier. Any large deviations should
be investigated further. Note that the input line voltage will have a significant impact on the
voltages measured. An ac input of 120 V ac is assumed. Note also that the bias setting will
have an impact on the voltages as well. With an ac input voltage of 120 V ac, the amplifier
should draw approximately 1.4 A with no audio input and with the bias set for –40 V dc. The
typical observable surge current at turn-on (from a cold start) is less than 2 A. The B+
voltage, as measured on Terminals #1 and #2 of the power supply PWB barrier strip is
typ425 V.
47) For the performance tests detailed in the next section, set the bias as follows:
• While monitoring terminal #2 of the right or left channel PWB barrier strip, set the Bias
Adjust potentiometer (R61) for –40 V.
• Check the B+ supply voltage at terminal #1 of the right or left channel PWB barrier strip.
With this bias setting a reading of approxi425 V dc should be observed.
• Check the ac line current. With this bias setting the amplifier should draw approximately
1.4 A.
V2, 7027A 1 425 V
2 28 V Heater, varies with setting of hum balance control
3 425 V
4 425 V
5 –40 V
6 –40 V
7 28 V Heater, varies with setting of hum balance control
8 –0 V
V3, 7027A 1 490 V
2 60 V Heater, varies with setting of hum balance control
3 490 V
4 425 V
5 –40 V
6 –40 V
7 28 V Heater, varies with setting of hum balance control
8 –0 V
Table 6.4 Typical Operating Voltages for Right and Left Channel Amplifiers with
No Signal Applied