| I decided that I
would try to rebuild a couple of amplifiers which had come my way
-- in each case the power supplies were in good shape but either
the output devices or driver circuitry had gone bad. One
such amplifier was an Audio Research D-120, the second was a crown
DC-150A. |
| The power supplies
of these amplifiers were relatively low voltage. To generate
the power which each were capable of I decided to use a bridged
configuration. In this case, each side of the amplifier will
swing to the absolute difference between rail voltages. A
shortcoming of the bridged configuration is that as each device
dissipates twice as much heat, requiring that the designer
parallel output devices to stay within the safe operating area of
the transistors. |
|
The schematic for the bridged
LM4702 amplifier is shown below. Note that gain for each
side is approximately 11X and total gain is 22X. |
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