Clipping caps in BMP

Frequent asked about building blocks: gain stages, buffers, clipping configurations, ...
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TV-Set
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Post by TV-Set »

Clipping caps in BMP (stages 2 and 3), why in some versions those are in front of the diodes and in others right after them? What influence does it have on the sound?

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Post by sinner »

funny, this is the question I wanted to ask today :D

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Post by phibes »

The cap is there to stop the clipping diodes from interfering with the transistor's bias, so doesn't matter if their in front, or in back of the diodes.
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Post by Dirk_Hendrik »

phibes wrote:The cap is there to stop the clipping diodes from interfering with the transistor's bias, so doesn't matter if their in front, or in back of the diodes.
Phibes is right.

Imagine (not so hard) that a cap is a full shortcut for AC. In that case in your circuit diagram the cap could be replaced by a wire. Now wonder wether it makes a difference if that wire is before or after the diodes. It's none. But that's AC only.
And therefore the cap is there to differentiate between DC (which indeed sets the transistor bias) and AC, which carries the toan. Only after this the discussion can start that a cap's impedance is not 0 for AC but 1/jwC and that it will conduct higher frequencies better, which in turn does influence that toan.

When you get to the point of seeing circuits from an AC as well as a DC perspective (at the same time) life gets so much easier. It is one of the prime targets to aim for while learnig to understand electronics.
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Post by TV-Set »

Dirk_Hendrik wrote:
phibes wrote:The cap is there to stop the clipping diodes from interfering with the transistor's bias, so doesn't matter if their in front, or in back of the diodes.
Phibes is right.

Imagine (not so hard) that a cap is a full shortcut for AC. In that case in your circuit diagram the cap could be replaced by a wire. Now wonder wether it makes a difference if that wire is before or after the diodes. It's none. But that's AC only.
And therefore the cap is there to differentiate between DC (which indeed sets the transistor bias) and AC, which carries the toan. Only after this the discussion can start that a cap's impedance is not 0 for AC but 1/jwC and that it will conduct higher frequencies better, which in turn does influence that toan.

When you get to the point of seeing circuits from an AC as well as a DC perspective (at the same time) life gets so much easier. It is one of the prime targets to aim for while learnig to understand electronics.
Looks like u know what you're saying there... any books or articles I should read? :) would appreciate that a lot

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Post by mictester »

TV-Set wrote: any books or articles I should read? :) would appreciate that a lot
"The Art Of Electronics" by Horowitz and Hill. There's not too much mathematics (you can't completely avoid it) and the descriptions of the way in which circuits function are superb.
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Post by TV-Set »

mictester wrote:
TV-Set wrote: any books or articles I should read? :) would appreciate that a lot
"The Art Of Electronics" by Horowitz and Hill. There's not too much mathematics (you can't completely avoid it) and the descriptions of the way in which circuits function are superb.
I'm not afraid of maths, I'm not a 12 year old kid, you see? :D Thank you, gonna find myself a copy

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