I'm looking at the schema of the Krell KSA 100 amp, and i'm puzzled with the 470uF caps in the emitter legs of the input stage, after the degeneration resistors...
What is their real use ? it seems, from simulation, that it can reduce the first harmonics level.
Thank You,
What is their real use ? it seems, from simulation, that it can reduce the first harmonics level.
Thank You,
Hello -
I agree with Hatasa. Increased gain from the first stage, but also increased distortion from the first stage due to lack of degeneration.
But then the increased overall loop gain translates to increased overall loop feedback, which reduces the closed loop distortion again.
Personally I prefer to keep the distortion to a minimum at each stage. Also, if the schematic is drawn correctly, there is a small AC signal across an unbiased electrolytic capacitor. This will also increase the distortion as the cap can be slightly reverse biased. Also, many people can hear the sonic signature from the electrolytic capacitor.
As always, there are lots of tradeoffs to choose from. Each person will make different choices.
Hope this helps,
Charles Hansen
I agree with Hatasa. Increased gain from the first stage, but also increased distortion from the first stage due to lack of degeneration.
But then the increased overall loop gain translates to increased overall loop feedback, which reduces the closed loop distortion again.
Personally I prefer to keep the distortion to a minimum at each stage. Also, if the schematic is drawn correctly, there is a small AC signal across an unbiased electrolytic capacitor. This will also increase the distortion as the cap can be slightly reverse biased. Also, many people can hear the sonic signature from the electrolytic capacitor.
As always, there are lots of tradeoffs to choose from. Each person will make different choices.
Hope this helps,
Charles Hansen
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