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Old 26th Feb 2016, 8:58 pm   #145
DangerMan
Heptode
 
Join Date: Jul 2009
Location: Stoke-on-Trent, Staffordshire, UK.
Posts: 700
Default Re: EL34 power amp project

Reducing the grid leak resistors won't affect the output power but means the driver stages have to work harder to achieve the same output as before. Also, the loop gain falls a bit.
Net result is that even at normal listening level there is a little bit less feedback and hence slightly more distortion due to that reduced feedback. But only a little bit.

There's no harm in temporarily bridging another 680K in parallel to see if it makes any difference to the overheating. Or you could reduce the dissipation without affecting the gain by slightly increasing the cathode resistances, especially if reducing the grid leaks makes no difference.

Pete
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