In the image below, what is the purpose of the circled bit? It is the preamp section of an 807 PP amp, and uses a direct coupled EF37 to 6SN7.
It is a bit hard to see, but there is a 220uF in series with a 12.5K resistor which goes from the grid of the 6SN7 to ground.
This is taken from http://hollowstate.netfirms.com/DIY_files/proto.htm
which is a great site and has a lot of interesting stuff on it.
Thanks!
It is a bit hard to see, but there is a 220uF in series with a 12.5K resistor which goes from the grid of the 6SN7 to ground.
This is taken from http://hollowstate.netfirms.com/DIY_files/proto.htm
which is a great site and has a lot of interesting stuff on it.
Thanks!
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Hi
Does this amplifier have global feedback? The reason I ask is that these kind of RC networks is sometimes used as phase compensation in feedback amplifiers in order to increase phase margin and reduce risk of oscillation, the RC network will reduce the phase shift at higher frequencies and therefore make the amplifier more stable, I use this kind of compensation in some of my amplifier designs.
If it is indeed used for this purpose I advice against removing it as it will increase risk of oscillation.
Regards Hans
Does this amplifier have global feedback? The reason I ask is that these kind of RC networks is sometimes used as phase compensation in feedback amplifiers in order to increase phase margin and reduce risk of oscillation, the RC network will reduce the phase shift at higher frequencies and therefore make the amplifier more stable, I use this kind of compensation in some of my amplifier designs.
If it is indeed used for this purpose I advice against removing it as it will increase risk of oscillation.
Regards Hans
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