 This amplifier has a fairly conventional CFP push pull output configuration, and has been tweaked
for speed, i.e. bandwidth, it is over 1MHz whilst delivering over 5 Amps in to a 1 ohm resistor. It is biased
loosely between 600 and 900mA for class A operation. Each channel has its own power transformer. The
voltage gain is provided by a current feedback video opamp, rated at 150MHz bandwidth. This is configured to
provide a non inverting gain and its output is coupled directly to the output stage. There is no overall
feedback. The pots are for triming the output DC offsets. The output power is currently about 10 watts, limited
by the opamps output swing.
I have been using this amplifier for 6 years and I am quite satisfied with its sound. Only the
smallest hint of grain is manifest from the video opamp, and this only became apparent when I swapped it for
the no mercy valve pre amp, as an experiment!
The only modification I have made to it is the addition of a power LED, so I don't forget to
turn it off!
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