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jim_beacon · 17th Sep 2006, 9:42 am

At low frequencies (<500Hz), there will be an in phase signal passed to both ouput grids, and that is not good! (if you don't believe me, do the maths - the component on one grid is very small, but it will cause some distortion). The circuit you have is a frequency dependant potential divider, so long as the capacitor is large, the effect won't be noticeable, but if it was less than the current value, it would. If you want to stick with this circuit, increase the cap to say 1uF, or even more

You should seperate the AC ground of the two grids really.

Jim.

17th Sep 2006, 9:42 am	#9
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: 807 power amp #1 At low frequencies (<500Hz), there will be an in phase signal passed to both ouput grids, and that is not good! (if you don't believe me, do the maths - the component on one grid is very small, but it will cause some distortion). The circuit you have is a frequency dependant potential divider, so long as the capacitor is large, the effect won't be noticeable, but if it was less than the current value, it would. If you want to stick with this circuit, increase the cap to say 1uF, or even more You should seperate the AC ground of the two grids really. Jim.