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Old 4th August 2012, 08:40 PM   #541
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ZM, In Aleph and other modulated current sources, a cap is need two pass copy of AC signal to CS. Is this necessary with transformers?
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Old 4th August 2012, 09:05 PM   #542
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small signal xformers aren't made , usually , for passing any sort of DC ......... if they are , they aren't small no more

so - regarding needs of biasing those bloody gates , xformer would see between 2V5-3V (depending what value of Rs Papa chose ) so ......... you can freely expect some cap in series with each secondary

that was the case always and always will be

we all know that Papa like Silmics and their sonic signature , so prepare ..... ok - you tell me which value is cunnin' to have there ?

as example of olde times - lookielookie (also as confirmation of Papa's words that amp is pure classic ) - so two pics of pure golden classics

on one of them you'll see clever way of avoiding caps ...... but that's also having some other penalties , so my - as always humble - thinking is that using cap is still most prominent way of doing it
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Old 4th August 2012, 09:17 PM   #543
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Wasnt even thinking in terms of DC blocking. SO stupid
You had to show me bJT's.
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Old 4th August 2012, 09:21 PM   #544
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no way Bubba

it's well known who's Master of Dumbness around here

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Old 4th August 2012, 09:35 PM   #545
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So small value resistors set bias, 400R resistor is local feedback setting gain, and cap does what? It seems to be pulling double duty?
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Old 4th August 2012, 09:52 PM   #546
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don't look at that , as example worth here too much - currents are way too high for our case ...... due to less demanding control electrode ( base vs. gate ) we can make it more elegant

everything is , say , double duty there - small resistors are shunting secondary and biasing base of bjt in same time ; 400R is creeping current through small resistors , shunting secondary too

I posted that schm as example , where even feedback path is of same logic as in F6 (you can ignore Q13 in series with primary)

betchya that we'll find few more caps in F6, across pots in bias nets ; Papa seeded way too much simple machines around , and each of them is containing trick or two

puzzles , puzzles everywhere ........
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Old 4th August 2012, 10:50 PM   #547
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I know, just practicing.
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Old 4th August 2012, 11:05 PM   #548
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repetitio est mater studiorum

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Old 4th August 2012, 11:45 PM   #549
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Anybody given thought to DC offset of the output stage? (besides NP)
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Old 4th August 2012, 11:53 PM   #550
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presumably normal ?
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