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Old 12th October 2009, 04:30 PM   #181
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In other words: The lower resistor, serial connected to the load, develops a voltage across itsef which, through a biasing voltage source, modulates the current source Jfet

Last edited by bobodioulasso; 12th October 2009 at 04:55 PM.
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Old 12th October 2009, 05:09 PM   #182
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Quote:
Originally Posted by bobodioulasso View Post
In other words: The lower resistor, serial connected to the load, develops a voltage across itsef which, through a biasing voltage source, modulates the current source Jfet
it's always like that - when you have SRPP

question is - why that resistor is divided in two



anyway - I imagine that two ( identical ) resistors are used to ensure equal Ri of upper and lower halve , looking from load side ..... or adequate output impedance , if you wish ;

imagine that you have just source resistor in upper halve , with value of these two resistors ; that's good enough for Shunt Regulating upper side of Push Pull .

but - these two halves will not have same or "enough" same internal resistance , and result must be in some asymmetric behavior ;

that's usually not of importance in tube stages , where bias voltage is negligible comparing to output swing ( not taking output impedance in account this time ...... or output signal tapping point) but - here - 1V2 certainly isn't same as 2V4 - comparing to overall voltage of 2x20V++
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Last edited by Zen Mod; 12th October 2009 at 05:20 PM.
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Old 12th October 2009, 05:18 PM   #183
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I see the upper resistor as a feedback to the current source variations.
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Old 14th October 2009, 08:29 AM   #184
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Quote:
Originally Posted by Zen Mod View Post
...imagine that you have just source resistor in upper halve , with value of these two resistors ; that's good enough for Shunt Regulating upper side of Push Pull ...
Aren't we in a single ended topology rather than a push pull one?
Te upper resistor is not in the output signal path but is part of the current source.
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Old 14th October 2009, 03:24 PM   #185
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Quote:
Originally Posted by Zen Mod View Post
question is - why that resistor is divided in two
The SRPP circuit diagrams as seen at John Broskie's Guide to Tube Circuit Analysis & Design have one resistor, and this maximizes the modulation of the current source tube. If you tap the load below the resistor, then you are going for a constant current source.

Tapping off the "middle" of the resistors, that is to say between two resistors, sets a middle performance, which is referred to there as the "mu follower".

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Old 14th October 2009, 06:35 PM   #186
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Quote:
Originally Posted by Nelson Pass View Post
The SRPP circuit diagrams as seen at John Broskie's Guide to Tube Circuit Analysis & Design have one resistor, and this maximizes the modulation of the current source tube. If you tap the load below the resistor, then you are going for a constant current source.

Tapping off the "middle" of the resistors, that is to say between two resistors, sets a middle performance, which is referred to there as the "mu follower".

So with a novices eyes, this 'Aikido mu follower'appears to be a close representation of the J2 simplified circuit.

The two tubes on the left are replaced by 2x 2sk170 on top, and 2sj109 on bottom on the negative rail. Followed by the SemiSouth JFETs.

Of course, I think that's what Nelson said....
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Old 14th October 2009, 09:58 PM   #187
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Hmmmm...

No, that's not it.
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Old 15th October 2009, 02:14 AM   #188
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page 3 is out on 6moons.
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Old 15th October 2009, 04:10 AM   #189
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Old 15th October 2009, 04:36 AM   #190
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