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洋人设计,实做测试过
曲线图
GU50 in parallel SE
HT 450V
Screens 300V
-46 volts bias @ 60mA for 27W dissipation
Sine wave test 200mV 1K
8W very clean (10% distortion)
11W on the visual onset of clipping (CRO)
Full power 18W
What was happening though was the screen supply was dropping to 275 volts under load. The regulator is meant to output 250mA but was giving up with only a 25mA load so I need to investigate that further.
As an experiment (valves are cheap) I connected the un-regulated supply to the screens, (314V under load) and achieved an output of 25Ws with the screens only dropping a small amount.
The 3K OT load produce slightly less power than the 2K3 which tends to agree with the consensus of a 5K load
Sound testing with guitar, it needs a tone control. Clean is very clear and defined but as the volume increases it sounds too hi-fi like.
Anyway, just a learning experience and practice driving my test tools (new distortion meter) |
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