| 摘要 |
PURPOSE:To obtain an output which has high quality in a high frequency band by using an amplifier tube which a has small resistance for an initial and a trailing stage amplification stage and further using a small load resistance for the resistance coupling between the initial and trailing stages. CONSTITUTION:The initial and trailing stage amplifier tubes (V1, and V2a and V2b) are composed amplifier tubes (6DJB, etc.) having an internal resistance (<=4kOMEGA) less than a half as large as that of an amplifier (12AU7, etc.) which is used principally and conventionally, and load resistances R4, R6 and R7 have values less than 8kOMEGA less than one fifth as large as a load value which is used principally and conventionally. Consequently, high frequency characteristics of respective stages based principally upon decreases in output impedance of the initial and trailing stages are improved greatly and the initial and trailing stages have a band width of >=0.6MHz totally. The frequency characteristics are more than about four times as large as those of an output stage (including output transformer), so a stagger ratio required for negative feedback is secured by the difference between the both.
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