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楼主 |
发表于 2012-4-12 15:09
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Great as the feedforward shunt regulator is at rejecting power-supply-induced noise, it does little to attenuate the signal-induced rail noise. The following circuit addresses that problem.
Remember that the EL84 holds two grids and that both control the flow of current through the tube. In the above circuit, we take advantage of the second grid. The 12AX7 triode is configured in a grounded-grid topology, which offers wide bandwidth and no phase inversion. The 12AU7 works in a cathode follower circuit and it directly drives the EL84’s grid number 2 with a greatly amplified rail noise signal. This might not be enough.
What might prove best is to use both a feedforward shunt regulator and a conventional shunt regulator at once, so that the first may eliminate the rectifier noise and the second, the signal-induced noise caused by the different stages within the amplifier tugging and pulling on the B+ rail.
原文出自:http://www.tubecad.com/2007/01/blog0095.htm |
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